: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH error n "" Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME error \- Generate an error .SH SYNOPSIS \fBerror \fImessage\fR ?\fIinfo\fR? ?\fIcode\fR? .BE .SH DESCRIPTION .PP Returns a \fBTCL_ERROR\fR code, which causes command interpretation to be unwound. \fIMessage\fR is a string that is returned to the application to indicate what went wrong. .PP If the \fIinfo\fR argument is provided and is non-empty, it is used to initialize the global variable \fBerrorInfo\fR. \fBerrorInfo\fR is used to accumulate a stack trace of what was in progress when an error occurred; as nested commands unwind, the Tcl interpreter adds information to \fBerrorInfo\fR. If the \fIinfo\fR argument is present, it is used to initialize \fBerrorInfo\fR and the first increment of unwind information will not be added by the Tcl interpreter. In other words, the command containing the \fBerror\fR command will not appear in \fBerrorInfo\fR; in its place will be \fIinfo\fR. This feature is most useful in conjunction with the \fBcatch\fR command: if a caught error cannot be handled successfully, \fIinfo\fR can be used to return a stack trace reflecting the original point of occurrence of the error: .CS \fBcatch {...} errMsg set savedInfo $errorInfo \&... error $errMsg $savedInfo\fR .CE .PP If the \fIcode\fR argument is present, then its value is stored in the \fBerrorCode\fR global variable. This variable is intended to hold a machine-readable description of the error in cases where such information is available; see the \fBtclvars\fR manual page for information on the proper format for the variable. If the \fIcode\fR argument is not present, then \fBerrorCode\fR is automatically reset to ``NONE'' by the Tcl interpreter as part of processing the error generated by the command. .SH EXAMPLE Generate an error if a basic mathematical operation fails: .CS if {1+2 != 3} { \fBerror\fR "something is very wrong with addition" } .CE .SH "SEE ALSO" catch(n), return(n), tclvars(n) .SH KEYWORDS error, errorCode, errorInfo '\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: read.n,v 1.7.8.1 2004/10/27 14:23:57 dkf Exp $ '\" '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?version? ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. The first argument is ignored and used for recording '\" the version when the .VS was added, so that the sidebars can be '\" found and removed when they reach a certain age. If another argument '\" is present, then a line break is forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b '\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. '\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out '\" # BS - start boxed text '\" # ^y = starting y location '\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. '\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. '\" # VS - start vertical sidebar '\" # ^Y = starting y location '\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. '\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. '\" # Special macro to handle page bottom: finish off current '\" # box/sidebar if in box/sidebar mode, then invoked standard '\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. '\" # DS - begin display .de DS .RS .nf .sp .. '\" # DE - end display .de DE .fi .RE .sp .. '\" # SO - start of list of standard options .de SO .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. '\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\fBoptions\\fR manual entry for details on the standard options. .. '\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH read n 8.1 Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME read \- Read from a channel .SH SYNOPSIS \fBread \fR?\fB\-nonewline\fR? \fIchannelId\fR .sp \fBread \fIchannelId numChars\fR .BE .SH DESCRIPTION .PP In the first form, the \fBread\fR command reads all of the data from \fIchannelId\fR up to the end of the file. If the \fB\-nonewline\fR switch is specified then the last character of the file is discarded if it is a newline. In the second form, the extra argument specifies how many characters to read. Exactly that many characters will be read and returned, unless there are fewer than \fInumChars\fR left in the file; in this case all the remaining characters are returned. If the channel is configured to use a multi-byte encoding, then the number of characters read may not be the same as the number of bytes read. .PP .VS \fIChannelId\fR must be an identifier for an open channel such as the Tcl standard input channel (\fBstdin\fR), the return value from an invocation of \fBopen\fR or \fBsocket\fR, or the result of a channel creation command provided by a Tcl extension. The channel must have been opened for input. .VE .PP If \fIchannelId\fR is in nonblocking mode, the command may not read as many characters as requested: once all available input has been read, the command will return the data that is available rather than blocking for more input. If the channel is configured to use a multi-byte encoding, then there may actually be some bytes remaining in the internal buffers that do not form a complete character. These bytes will not be returned until a complete character is available or end-of-file is reached. The \fB\-nonewline\fR switch is ignored if the command returns before reaching the end of the file. .PP \fBRead\fR translates end-of-line sequences in the input into newline characters according to the \fB\-translation\fR option for the channel. See the \fBfconfigure\fR manual entry for a discussion on ways in which \fBfconfigure\fR will alter input. .SH "USE WITH SERIAL PORTS" '\" Note: this advice actually applies to many versions of Tcl For most applications a channel connected to a serial port should be configured to be nonblocking: \fBfconfigure \fIchannelId \fB\-blocking \fI0\fR. Then \fBread\fR behaves much like described above. Care must be taken when using \fBread\fR on blocking serial ports: .TP \fBread \fIchannelId numChars\fR In this form \fBread\fR blocks until \fInumChars\fR have been received from the serial port. .TP \fBread \fIchannelId\fR In this form \fBread\fR blocks until the reception of the end-of-file character, see \fBfconfigure -eofchar\fR. If there no end-of-file character has been configured for the channel, then \fBread\fR will block forever. .SH "EXAMPLE" This example code reads a file all at once, and splits it into a list, with each line in the file corresponding to an element in the list: .CS set fl [open /proc/meminfo] set data [\fBread\fR $fl] close $fl set lines [split $data \\n] .CE .SH "SEE ALSO" file(n), eof(n), fblocked(n), fconfigure(n), Tcl_StandardChannels(3) .SH KEYWORDS blocking, channel, end of line, end of file, nonblocking, read, translation, encoding ü2 .÷$ ..ý2cpp.1þ2tclsh.1ÿ2gcov.13g++.13make.13˜gcc.1.\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05) .\" .\" Standard preamble: .\" ======================================================================== .de Sh \" Subsection heading .br .if t .Sp .ne 5 .PP \fB\\$1\fR .PP .. .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is turned on, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .ie \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . nr % 0 . rr F .\} .el \{\ . de IX .. .\} .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "CPP 1" .TH CPP 1 "2010-05-22" "gcc-4.3.5" "GNU" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" cpp \- The C Preprocessor .SH "SYNOPSIS" .IX Header "SYNOPSIS" cpp [\fB\-D\fR\fImacro\fR[=\fIdefn\fR]...] [\fB\-U\fR\fImacro\fR] [\fB\-I\fR\fIdir\fR...] [\fB\-iquote\fR\fIdir\fR...] [\fB\-W\fR\fIwarn\fR...] [\fB\-M\fR|\fB\-MM\fR] [\fB\-MG\fR] [\fB\-MF\fR \fIfilename\fR] [\fB\-MP\fR] [\fB\-MQ\fR \fItarget\fR...] [\fB\-MT\fR \fItarget\fR...] [\fB\-P\fR] [\fB\-fno\-working\-directory\fR] [\fB\-x\fR \fIlanguage\fR] [\fB\-std=\fR\fIstandard\fR] \fIinfile\fR \fIoutfile\fR .PP Only the most useful options are listed here; see below for the remainder. .SH "DESCRIPTION" .IX Header "DESCRIPTION" The C preprocessor, often known as \fIcpp\fR, is a \fImacro processor\fR that is used automatically by the C compiler to transform your program before compilation. It is called a macro processor because it allows you to define \fImacros\fR, which are brief abbreviations for longer constructs. .PP The C preprocessor is intended to be used only with C, \*(C+, and Objective-C source code. In the past, it has been abused as a general text processor. It will choke on input which does not obey C's lexical rules. For example, apostrophes will be interpreted as the beginning of character constants, and cause errors. Also, you cannot rely on it preserving characteristics of the input which are not significant to C\-family languages. If a Makefile is preprocessed, all the hard tabs will be removed, and the Makefile will not work. .PP Having said that, you can often get away with using cpp on things which are not C. Other Algol-ish programming languages are often safe (Pascal, Ada, etc.) So is assembly, with caution. \fB\-traditional\-cpp\fR mode preserves more white space, and is otherwise more permissive. Many of the problems can be avoided by writing C or \*(C+ style comments instead of native language comments, and keeping macros simple. .PP Wherever possible, you should use a preprocessor geared to the language you are writing in. Modern versions of the \s-1GNU\s0 assembler have macro facilities. Most high level programming languages have their own conditional compilation and inclusion mechanism. If all else fails, try a true general text processor, such as \s-1GNU\s0 M4. .PP C preprocessors vary in some details. This manual discusses the \s-1GNU\s0 C preprocessor, which provides a small superset of the features of \s-1ISO\s0 Standard C. In its default mode, the \s-1GNU\s0 C preprocessor does not do a few things required by the standard. These are features which are rarely, if ever, used, and may cause surprising changes to the meaning of a program which does not expect them. To get strict \s-1ISO\s0 Standard C, you should use the \fB\-std=c89\fR or \fB\-std=c99\fR options, depending on which version of the standard you want. To get all the mandatory diagnostics, you must also use \fB\-pedantic\fR. .PP This manual describes the behavior of the \s-1ISO\s0 preprocessor. To minimize gratuitous differences, where the \s-1ISO\s0 preprocessor's behavior does not conflict with traditional semantics, the traditional preprocessor should behave the same way. The various differences that do exist are detailed in the section \fBTraditional Mode\fR. .PP For clarity, unless noted otherwise, references to \fB\s-1CPP\s0\fR in this manual refer to \s-1GNU\s0 \s-1CPP\s0. .SH "OPTIONS" .IX Header "OPTIONS" The C preprocessor expects two file names as arguments, \fIinfile\fR and \&\fIoutfile\fR. The preprocessor reads \fIinfile\fR together with any other files it specifies with \fB#include\fR. All the output generated by the combined input files is written in \fIoutfile\fR. .PP Either \fIinfile\fR or \fIoutfile\fR may be \fB\-\fR, which as \&\fIinfile\fR means to read from standard input and as \fIoutfile\fR means to write to standard output. Also, if either file is omitted, it means the same as if \fB\-\fR had been specified for that file. .PP Unless otherwise noted, or the option ends in \fB=\fR, all options which take an argument may have that argument appear either immediately after the option, or with a space between option and argument: \&\fB\-Ifoo\fR and \fB\-I foo\fR have the same effect. .PP Many options have multi-letter names; therefore multiple single-letter options may \fInot\fR be grouped: \fB\-dM\fR is very different from \&\fB\-d\ \-M\fR. .IP "\fB\-D\fR \fIname\fR" 4 .IX Item "-D name" Predefine \fIname\fR as a macro, with definition \f(CW1\fR. .IP "\fB\-D\fR \fIname\fR\fB=\fR\fIdefinition\fR" 4 .IX Item "-D name=definition" The contents of \fIdefinition\fR are tokenized and processed as if they appeared during translation phase three in a \fB#define\fR directive. In particular, the definition will be truncated by embedded newline characters. .Sp If you are invoking the preprocessor from a shell or shell-like program you may need to use the shell's quoting syntax to protect characters such as spaces that have a meaning in the shell syntax. .Sp If you wish to define a function-like macro on the command line, write its argument list with surrounding parentheses before the equals sign (if any). Parentheses are meaningful to most shells, so you will need to quote the option. With \fBsh\fR and \fBcsh\fR, \&\fB\-D'\fR\fIname\fR\fB(\fR\fIargs...\fR\fB)=\fR\fIdefinition\fR\fB'\fR works. .Sp \&\fB\-D\fR and \fB\-U\fR options are processed in the order they are given on the command line. All \fB\-imacros\fR \fIfile\fR and \&\fB\-include\fR \fIfile\fR options are processed after all \&\fB\-D\fR and \fB\-U\fR options. .IP "\fB\-U\fR \fIname\fR" 4 .IX Item "-U name" Cancel any previous definition of \fIname\fR, either built in or provided with a \fB\-D\fR option. .IP "\fB\-undef\fR" 4 .IX Item "-undef" Do not predefine any system-specific or GCC-specific macros. The standard predefined macros remain defined. .IP "\fB\-I\fR \fIdir\fR" 4 .IX Item "-I dir" Add the directory \fIdir\fR to the list of directories to be searched for header files. .Sp Directories named by \fB\-I\fR are searched before the standard system include directories. If the directory \fIdir\fR is a standard system include directory, the option is ignored to ensure that the default search order for system directories and the special treatment of system headers are not defeated \&. If \fIdir\fR begins with \f(CW\*(C`=\*(C'\fR, then the \f(CW\*(C`=\*(C'\fR will be replaced by the sysroot prefix; see \fB\-\-sysroot\fR and \fB\-isysroot\fR. .IP "\fB\-o\fR \fIfile\fR" 4 .IX Item "-o file" Write output to \fIfile\fR. This is the same as specifying \fIfile\fR as the second non-option argument to \fBcpp\fR. \fBgcc\fR has a different interpretation of a second non-option argument, so you must use \fB\-o\fR to specify the output file. .IP "\fB\-Wall\fR" 4 .IX Item "-Wall" Turns on all optional warnings which are desirable for normal code. At present this is \fB\-Wcomment\fR, \fB\-Wtrigraphs\fR, \&\fB\-Wmultichar\fR and a warning about integer promotion causing a change of sign in \f(CW\*(C`#if\*(C'\fR expressions. Note that many of the preprocessor's warnings are on by default and have no options to control them. .IP "\fB\-Wcomment\fR" 4 .IX Item "-Wcomment" .PD 0 .IP "\fB\-Wcomments\fR" 4 .IX Item "-Wcomments" .PD Warn whenever a comment-start sequence \fB/*\fR appears in a \fB/*\fR comment, or whenever a backslash-newline appears in a \fB//\fR comment. (Both forms have the same effect.) .IP "\fB\-Wtrigraphs\fR" 4 .IX Item "-Wtrigraphs" Most trigraphs in comments cannot affect the meaning of the program. However, a trigraph that would form an escaped newline (\fB??/\fR at the end of a line) can, by changing where the comment begins or ends. Therefore, only trigraphs that would form escaped newlines produce warnings inside a comment. .Sp This option is implied by \fB\-Wall\fR. If \fB\-Wall\fR is not given, this option is still enabled unless trigraphs are enabled. To get trigraph conversion without warnings, but get the other \&\fB\-Wall\fR warnings, use \fB\-trigraphs \-Wall \-Wno\-trigraphs\fR. .IP "\fB\-Wtraditional\fR" 4 .IX Item "-Wtraditional" Warn about certain constructs that behave differently in traditional and \&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C equivalent, and problematic constructs which should be avoided. .IP "\fB\-Wimport\fR" 4 .IX Item "-Wimport" Warn the first time \fB#import\fR is used. .IP "\fB\-Wundef\fR" 4 .IX Item "-Wundef" Warn whenever an identifi\\\\\\ \!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\0\1\2\3\4\5\er which is not a macro is encountered in an \&\fB#if\fR directive, outside of \fBdefined\fR. Such identifiers are replaced with zero. .IP "\fB\-Wunused\-macros\fR" 4 .IX Item "-Wunused-macros" Warn about macros defined in the main file that are unused. A macro is \fIused\fR if it is expanded or tested for existence at least once. The preprocessor will also warn if the macro has not been used at the time it is redefined or undefined. .Sp Built-in macros, macros defined on the command line, and macros defined in include files are not warned about. .Sp \&\fINote:\fR If a macro is actually used, but only used in skipped conditional blocks, then \s-1CPP\s0 will report it as unused. To avoid the warning in such a case, you might improve the scope of the macro's definition by, for example, moving it into the first skipped block. Alternatively, you could provide a dummy use with something like: .Sp .Vb 2 \& #if defined the_macro_causing_the_warning \& #endif .Ve .IP "\fB\-Wendif\-labels\fR" 4 .IX Item "-Wendif-labels" Warn whenever an \fB#else\fR or an \fB#endif\fR are followed by text. This usually happens in code of the form .Sp .Vb 5 \& #if FOO \& ... \& #else FOO \& ... \& #endif FOO .Ve .Sp The second and third \f(CW\*(C`FOO\*(C'\fR should be in comments, but often are not in older programs. This warning is on by default. .IP "\fB\-Werror\fR" 4 .IX Item "-Werror" Make all warnings into hard errors. Source code which triggers warnings will be rejected. .IP "\fB\-Wsystem\-headers\fR" 4 .IX Item "-Wsystem-headers" Issue warnings for code in system headers. These are normally unhelpful in finding bugs in your own code, therefore suppressed. If you are responsible for the system library, you may want to see them. .IP "\fB\-w\fR" 4 .IX Item "-w" Suppress all warnings, including those which \s-1GNU\s0 \s-1CPP\s0 issues by default. .IP "\fB\-pedantic\fR" 4 .IX Item "-pedantic" Issue all the mandatory diagnostics listed in the C standard. Some of them are left out by default, since they trigger frequently on harmless code. .IP "\fB\-pedantic\-errors\fR" 4 .IX Item "-pedantic-errors" Issue all the mandatory diagnostics, and make all mandatory diagnostics into errors. This includes mandatory diagnostics that \s-1GCC\s0 issues without \fB\-pedantic\fR but treats as warnings. .IP "\fB\-M\fR" 4 .IX Item "-M" Instead of outputting the result of preprocessing, output a rule suitable for \fBmake\fR describing the dependencies of the main source file. The preprocessor outputs one \fBmake\fR rule containing the object file name for that source file, a colon, and the names of all the included files, including those coming from \fB\-include\fR or \&\fB\-imacros\fR command line options. .Sp Unless specified explicitly (with \fB\-MT\fR or \fB\-MQ\fR), the object file name consists of the name of the source file with any suffix replaced with object file suffix and with any leading directory parts removed. If there are many included files then the rule is split into several lines using \fB\e\fR\-newline. The rule has no commands. .Sp This option does not suppress the preprocessor's debug output, such as \&\fB\-dM\fR. To avoid mixing such debug output with the dependency rules you should explicitly specify the dependency output file with \&\fB\-MF\fR, or use an environment variable like \&\fB\s-1DEPENDENCIES_OUTPUT\s0\fR. Debug output will still be sent to the regular output stream as normal. .Sp Passing \fB\-M\fR to the driver implies \fB\-E\fR, and suppresses warnings with an implicit \fB\-w\fR. .IP "\fB\-MM\fR" 4 .IX Item "-MM" Like \fB\-M\fR but do not mention header files that are found in system header directories, nor header files that are included, directly or indirectly, from such a header. .Sp This implies that the choice of angle brackets or double quotes in an \&\fB#include\fR directive does not in itself determine whether that header will appear in \fB\-MM\fR dependency output. This is a slight change in semantics from \s-1GCC\s0 versions 3.0 and earlier. .IP "\fB\-MF\fR \fIfile\fR" 4 .IX Item "-MF file" When used with \fB\-M\fR or \fB\-MM\fR, specifies a file to write the dependencies to. If no \fB\-MF\fR switch is given the preprocessor sends the rules to the same place it would have sent preprocessed output. .Sp When used with the driver options \fB\-MD\fR or \fB\-MMD\fR, \&\fB\-MF\fR overrides the default dependency output file. .IP "\fB\-MG\fR" 4 .IX Item "-MG" In conjunction with an option such as \fB\-M\fR requesting dependency generation, \fB\-MG\fR assumes missing header files are generated files and adds them to the dependency list without raising an error. The dependency filename is taken directly from the \&\f(CW\*(C`#include\*(C'\fR directive without prepending any path. \fB\-MG\fR also suppresses preprocessed output, as a missing header file renders this useless. .Sp This feature is used in automatic updating of makefiles. .IP "\fB\-MP\fR" 4 .IX Item "-MP" This option instructs \s-1CPP\s0 to add a phony target for each dependency other than the main file, causing each to depend on nothing. These dummy rules work around errors \fBmake\fR gives if you remove header files without updating the \fIMakefile\fR to match. .Sp This is typical output: .Sp .Vb 1 \& test.o: test.c test.h \& \& test.h: .Ve .IP "\fB\-MT\fR \fItarget\fR" 4 .IX Item "-MT target" Change the target of the rule emitted by dependency generation. By default \s-1CPP\s0 takes the name of the main input file, deletes any directory components and any file suffix such as \fB.c\fR, and appends the platform's usual object suffix. The result is the target. .Sp An \fB\-MT\fR option will set the target to be exactly the string you specify. If you want multiple targets, you can specify them as a single argument to \fB\-MT\fR, or use multiple \fB\-MT\fR options. .Sp For example, \fB\-MT\ '$(objpfx)foo.o'\fR might give .Sp .Vb 1 \& $(objpfx)foo.o: foo.c .Ve .IP "\fB\-MQ\fR \fItarget\fR" 4 .IX Item "-MQ target" Same as \fB\-MT\fR, but it quotes any characters which are special to Make. \fB\-MQ\ '$(objpfx)foo.o'\fR gives .Sp .Vb 1 \& $$(objpfx)foo.o: foo.c .Ve .Sp The default target is automatically quoted, as if it were given with \&\fB\-MQ\fR. .IP "\fB\-MD\fR" 4 .IX Item "-MD" \&\fB\-MD\fR is equivalent to \fB\-M \-MF\fR \fIfile\fR, except that \&\fB\-E\fR is not implied. The driver determines \fIfile\fR based on whether an \fB\-o\fR option is given. If it is, the driver uses its argument but with a suffix of \fI.d\fR, otherwise it takes the name of the input file, removes any directory components and suffix, and applies a \fI.d\fR suffix. .Sp If \fB\-MD\fR is used in conjunction with \fB\-E\fR, any \&\fB\-o\fR switch is understood to specify the dependency output file, but if used without \fB\-E\fR, each \fB\-o\fR is understood to specify a target object file. .Sp Since \fB\-E\fR is not implied, \fB\-MD\fR can be used to generate a dependency output file as a side-effect of the compilation process. .IP "\fB\-MMD\fR" 4 .IX Item "-MMD" Like \fB\-MD\fR except mention only user header files, not system header files. .IP "\fB\-x c\fR" 4 .IX Item "-x c" .PD 0 .IP "\fB\-x c++\fR" 4 .IX Item "-x c++" .IP "\fB\-x objective-c\fR" 4 .IX Item "-x objective-c" .IP "\fB\-x assembler-with-cpp\fR" 4 .IX Item "-x assembler-with-cpp" .PD Specify the source language: C, \*(C+, Objective-C, or assembly. This has nothing to do with standards conformance or extensions; it merely selects which base syntax to expect. If you give none of these options, cpp will deduce the language from the extension of the source file: \&\fB.c\fR, \fB.cc\fR, \fB.m\fR, or \fB.S\fR. Some other common extensions for \*(C+ and assembly are also recognized. If cpp does not recognize the extension, it will treat the file as C; this is the most generic mode. .Sp \&\fINote:\fR Previous versions of cpp accepted a \fB\-lang\fR option which selected both the language and the standards conformance level. This option has been removed, because it conflicts with the \fB\-l\fR option. .IP "\fB\-std=\fR\fIstandard\fR" 4 .IX Item "-std=standard" .PD 0 .IP "\fB\-ansi\fR" 4 .IX Item "-ansi" .PD Specify the standard to which the code should conform. Currently \s-1CPP\s0 knows about C and \*(C+ standards; others may be added in the future. .Sp \&\fIstandard\fR may be one of: .RS 4 .ie n .IP """iso9899:1990""" 4 .el .IP "\f(CWiso9899:1990\fR" 4 .IX Item "iso9899:1990" .PD 0 .ie n .IP """c89""" 4 .el .IP "\f(CWc89\fR" 4 .IX Item "c89" .PD The \s-1ISO\s0 C standard from 1990. \fBc89\fR is the customary shorthand for this version of the standard. .Sp The \fB\-ansi\fR option is equivalent to \fB\-std=c89\fR. .ie n .IP """iso9899:199409""" 4 .el .IP "\f(CWiso9899:199409\fR" 4 .IX Item "iso9899:199409" The 1990 C standard, as amended in 1994. .ie n .IP """iso9899:1999""" 4 .el .IP "\f(CWiso9899:1999\fR" 4 .IX Item "iso9899:1999" .PD 0 .ie n .IP """c99""" 4 .el .IP "\f(CWc99\fR" 4 .IX Item "c99" .ie n .IP """iso9899:199x""" 4 .el .IP "\f(CWiso9899:199x\fR" 4 .IX Item "iso9899:199x" .ie n .IP """c9x""" 4 .el .IP "\f(CWc9x\fR" 4 .IX Item "c9x" .PD The revised \s-1ISO\s0 C standard, published in December 1999. Before publication, this was known as C9X. .ie n .IP """gnu89""" 4 .el .IP "\f(CWgnu89\fR" 4 .IX Item "gnu89" The 1990 C standard plus \s-1GNU\s0 extensions. This is the default. .ie n .IP """gnu99""" 4 .el .IP "\f(CWgnu99\fR" 4 .IX Item "gnu99" .PD 0 .ie n .IP """gnu9x""" 4 .el .IP "\f(CWgnu9x\fR" 4 .IX Item "gnu9x" .PD The 1999 C standard plus \s-1GNU\s0 extensions. .ie n .IP """c++98""" 4 .el .IP "\f(CWc++98\fR" 4 .IX Item "c++98" The 1998 \s-1ISO\s0 \*(C+ standard plus amendments. .ie n .IP """gnu++98""" 4 .el .IP "\f(CWgnu++98\fR" 4 .IX Item "gnu++98" The same as \fB\-std=c++98\fR plus \s-1GNU\s0 extensions. This is the default for \*(C+ code. .RE .RS 4 .RE .IP "\fB\-I\-\fR" 4 .IX Item "-I-" Split the include path. Any directories specified with \fB\-I\fR options before \fB\-I\-\fR are searched only for headers requested with \&\f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR; they are not searched for \&\f(CW\*(C`#include\ <\f(CIfile\f(CW>\*(C'\fR. If additional directories are specified with \fB\-I\fR options after the \fB\-I\-\fR, those directories are searched for all \fB#include\fR directives. .Sp In addition, \fB\-I\-\fR inhibits the use of the directory of the current file directory as the first search directory for \f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR. .Sp This option has been deprecated. .IP "\fB\-nostdinc\fR" 4 .IX Item "-nostdinc" Do not search the standard system directories for header files. Only the directories you have specified with \fB\-I\fR options (and the directory of the current file, if appropriate) are searched. .IP "\fB\-nostdinc++\fR" 4 .IX Item "-nostdinc++" Do not search for header files in the \*(C+\-specific standard directories, but do still search the other standard directories. (This option is used when building the \*(C+ library.) .IP "\fB\-include\fR \fIfile\fR" 4 .IX Item "-include file" Process \fIfile\fR as if \f(CW\*(C`#include "file"\*(C'\fR appeared as the first line of the primary source file. However, the first directory searched for \fIfile\fR is the preprocessor's working directory \fIinstead of\fR the directory containing the main source file. If not found there, it is searched for in the remainder of the \f(CW\*(C`#include "..."\*(C'\fR search chain as normal. .Sp If multiple \fB\-include\fR options are given, the files are included in the order they appear on the command line. .IP "\fB\-imacros\fR \fIfile\fR" 4 .IX Item "-imacros file" Exactly like \fB\-include\fR, except that any output produced by scanning \fIfile\fR is thrown away. Macros it defines remain defined. This allows you to acquire all the macros from a header without also processing its declarations. .Sp All files specified by \fB\-imacros\fR are processed before all files specified by \fB\-include\fR. .IP "\fB\-idirafter\fR \fIdir\fR" 4 .IX Item "-idirafter dir" Search \fIdir\fR for header files, but do it \fIafter\fR all directories specified with \fB\-I\fR and the standard system directories have been exhausted. \fIdir\fR is treated as a system include directory. If \fIdir\fR begins with \f(CW\*(C`=\*(C'\fR, then the \f(CW\*(C`=\*(C'\fR will be replaced by the sysroot prefix; see \fB\-\-sysroot\fR and \fB\-isysroot\fR. .IP "\fB\-iprefix\fR \fIprefix\fR" 4 .IX Item "-iprefix prefix" Specify \fIprefix\fR as the prefix for subsequent \fB\-iwithprefix\fR options. If the prefix represents a directory, you should include the final \fB/\fR. .IP "\fB\-iwithprefix\fR \fIdir\fR" 4 .IX Item "-iwithprefix dir" .PD 0 .IP "\fB\-iwithprefixbefore\fR \fIdir\fR" 4 .IX Item "-iwithprefixbefore dir" .PD Append \fIdir\fR to the prefix specified previously with \&\fB\-iprefix\fR, and add the resulting directory to the include search path. \fB\-iwithprefixbefore\fR puts it in the same place \fB\-I\fR would; \fB\-iwithprefix\fR puts it where \fB\-idirafter\fR would. .IP "\fB\-isysroot\fR \fIdir\fR" 4 .IX Item "-isysroot dir" This option is like the \fB\-\-sysroot\fR option, but applies only to header files. See the \fB\-\-sysroot\fR option for more information. .IP "\fB\-imultilib\fR \fIdir\fR" 4 .IX Item "-imultilib dir" Use \fIdir\fR as a subdirectory of the directory containing target-specific \*(C+ headers. .IP "\fB\-isystem\fR \fIdir\fR" 4 .IX Item "-isystem dir" Search \fIdir\fR for header files, after all directories specified by \&\fB\-I\fR but before the standard system directories. Mark it as a system directory, so that it gets the same special treatment as is applied to the standard system directories. .Sp If \fIdir\fR begins with \f(CW\*(C`=\*(C'\fR, then the \f(CW\*(C`=\*(C'\fR will be replaced by the sysroot prefix; see \fB\-\-sysroot\fR and \fB\-isysroot\fR. .IP "\fB\-iquote\fR \fIdir\fR" 4 .IX Item "-iquote dir" Search \fIdir\fR only for header files requested with \&\f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR; they are not searched for \&\f(CW\*(C`#include\ <\f(CIfile\f(CW>\*(C'\fR, before all directories specified by \&\fB\-I\fR and before the standard system directories. .Sp If \fIdir\fR begins with \f(CW\*(C`=\*(C'\fR, then the \f(CW\*(C`=\*(C'\fR will be replaced by the sysroot prefix; see \fB\-\-sysroot\fR and \fB\-isysroot\fR. .IP "\fB\-fdirectives\-only\fR" 4 .IX Item "-fdirectives-only" When preprocessing, handle directives, but do not expand macros. .Sp The option's behavior depends on the \fB\-E\fR and \fB\-fpreprocessed\fR options. .Sp With \fB\-E\fR, preprocessing is limited to the handling of directives such as \f(CW\*(C`#define\*(C'\fR, \f(CW\*(C`#ifdef\*(C'\fR, and \f(CW\*(C`#error\*(C'\fR. Other preprocessor operations, such as macro expansion and trigraph conversion are not performed. In addition, the \fB\-dD\fR option is implicitly enabled. .Sp With \fB\-fpreprocessed\fR, predefinition of command line and most builtin macros is disabled. Macros such as \f(CW\*(C`_\|_LINE_\|_\*(C'\fR, which are contextually dependent, are handled normally. This enables compilation of files previously preprocessed with \f(CW\*(C`\-E \-fdirectives\-only\*(C'\fR. .Sp With both \fB\-E\fR and \fB\-fpreprocessed\fR, the rules for \&\fB\-fpreprocessed\fR take precedence. This enables full preprocessing of files previously preprocessed with \f(CW\*(C`\-E \-fdirectives\-only\*(C'\fR. .IP "\fB\-fdollars\-in\-identifiers\fR" 4 .IX Item "-fdollars-in-identifiers" Accept \fB$\fR in identifiers. .IP "\fB\-fextended\-identifiers\fR" 4 .IX Item "-fextended-identifiers" Accept universal character names in identifiers. This option is experimental; in a future version of \s-1GCC\s0, it will be enabled by default for C99 and \*(C+. .IP "\fB\-fpreprocessed\fR" 4 .IX Item "-fpreprocessed" Indicate to the preprocessor that the input file has already been preprocessed. This suppresses things like macro expansion, trigraph conversion, escaped newline splicing, and processing of most directives. The preprocessor still recognizes and removes comments, so that you can pass a file preprocessed with \fB\-C\fR to the compiler without problems. In this mode the integrated preprocessor is little more than a tokenizer for the front ends. .Sp \&\fB\-fpreprocessed\fR is implicit if the input file has one of the extensions \fB.i\fR, \fB.ii\fR or \fB.mi\fR. These are the extensions that \s-1GCC\s0 uses for preprocessed files created by \&\fB\-save\-temps\fR. .IP "\fB\-ftabstop=\fR\fIwidth\fR" 4 .IX Item "-ftabstop=width" Set the distance between tab stops. This helps the preprocessor report correct column numbers in warnings or errors, even if tabs appear on the line. If the value is less than 1 or greater than 100, the option is ignored. The default is 8. .IP "\fB\-fexec\-charset=\fR\fIcharset\fR" 4 .IX Item "-fexec-charset=charset" Set the execution character set, used for string and character constants. The default is \s-1UTF\-8\s0. \fIcharset\fR can be any encoding supported by the system's \f(CW\*(C`iconv\*(C'\fR library routine. .IP "\fB\-fwide\-exec\-charset=\fR\fIcharset\fR" 4 .IX Item "-fwide-exec-charset=charset" Set the wide execution character set, used for wide string and character constants. The default is \s-1UTF\-32\s0 or \s-1UTF\-16\s0, whichever corresponds to the width of \f(CW\*(C`wchar_t\*(C'\fR. As with \&\fB\-fexec\-charset\fR, \fIcharset\fR can be any encoding supported by the system's \f(CW\*(C`iconv\*(C'\fR library routine; however, you will have problems with encodings that do not fit exactly in \f(CW\*(C`wchar_t\*(C'\fR. .IP "\fB\-finput\-charset=\fR\fIcharset\fR" 4 .IX Item "-finput-charset=charset" Set the input character set, used for translation from the character set of the input file to the source character set used by \s-1GCC\s0. If the locale does not specify, or \s-1GCC\s0 cannot get this information from the locale, the default is \s-1UTF\-8\s0. This can be overridden by either the locale or this command line option. Currently the command line option takes precedence if there's a conflict. \fIcharset\fR can be any encoding supported by the system's \f(CW\*(C`iconv\*(C'\fR library routine. .IP "\fB\-fworking\-directory\fR" 4 .IX Item "-fworking-directory" Enable generation of linemarkers in the preprocessor output that will let the compiler know the current working directory at the time of preprocessing. When this option is enabled, the preprocessor will emit, after the initial linemarker, a second linemarker with the current working directory followed by two slashes. \s-1GCC\s0 will use this directory, when it's present in the preprocessed input, as the directory emitted as the current working directory in some debugging information formats. This option is implicitly enabled if debugging information is enabled, but this can be inhibited with the negated form \fB\-fno\-working\-directory\fR. If the \fB\-P\fR flag is present in the command line, this option has no effect, since no \&\f(CW\*(C`#line\*(C'\fR directives are emitted whatsoever. .IP "\fB\-fno\-show\-column\fR" 4 .IX Item "-fno-show-column" Do not print column numbers in diagnostics. This may be necessary if diagnostics are being scanned by a program that does not understand the column numbers, such as \fBdejagnu\fR. .IP "\fB\-A\fR \fIpredicate\fR\fB=\fR\fIanswer\fR" 4 .IX Item "-A predicate=answer" Make an assertion with the predicate \fIpredicate\fR and answer \&\fIanswer\fR. This form is preferred to the older form \fB\-A\fR \&\fIpredicate\fR\fB(\fR\fIanswer\fR\fB)\fR, which is still supported, because it does not use shell special characters. .IP "\fB\-A \-\fR\fIpredicate\fR\fB=\fR\fIanswer\fR" 4 .IX Item "-A -predicate=answer" Cancel an assertion with the predicate \fIpredicate\fR and answer \&\fIanswer\fR. .IP "\fB\-dCHARS\fR" 4 .IX Item "-dCHARS" \&\fI\s-1CHARS\s0\fR is a sequence of one or more of the following characters, and must not be preceded by a space. Other characters are interpreted by the compiler proper, or reserved for future versions of \s-1GCC\s0, and so are silently ignored. If you specify characters whose behavior conflicts, the result is undefined. .RS 4 .IP "\fBM\fR" 4 .IX Item "M" Instead of the normal output, generate a list of \fB#define\fR directives for all the macros defined during the execution of the preprocessor, including predefined macros. This gives you a way of finding out what is predefined in your version of the preprocessor. Assuming you have no file \fIfoo.h\fR, the command .Sp .Vb 1 \& touch foo.h; cpp \-dM foo.h .Ve .Sp will show all the predefined macros. .Sp If you use \fB\-dM\fR without the \fB\-E\fR option, \fB\-dM\fR is interpreted as a synonym for \fB\-fdump\-rtl\-mach\fR. .IP "\fBD\fR" 4 .IX Item "D" Like \fBM\fR except in two respects: it does \fInot\fR include the predefined macros, and it outputs \fIboth\fR the \fB#define\fR directives and the result of preprocessing. Both kinds of output go to the standard output file. .IP "\fBN\fR" 4 .IX Item "N" Like \fBD\fR, but emit only the macro names, not their expansions. .IP "\fBI\fR" 4 .IX Item "I" Output \fB#include\fR directives in addition to the result of preprocessing. .RE .RS 4 .RE .IP "\fB\-P\fR" 4 .IX Item "-P" Inhibit generation of linemarkers in the output from the preprocessor. This might be useful when running the preprocessor on something that is not C code, and will be sent to a program which might be confused by the linemarkers. .IP "\fB\-C\fR" 4 .IX Item "-C" Do not discard comments. All comments are passed through to the output file, except for comments in processed directives, which are deleted along with the directive. .Sp You should be prepared for side effects when using \fB\-C\fR; it causes the preprocessor to treat comments as tokens in their own right. For example, comments appearing at the start of what would be a directive line have the effect of turning that line into an ordinary source line, since the first token on the line is no longer a \fB#\fR. .IP "\fB\-CC\fR" 4 .IX Item "-CC" Do not discard comments, including during macro expansion. This is like \fB\-C\fR, except that comments contained within macros are also passed through to the output file where the macro is expanded. .Sp In addition to the side-effects of the \fB\-C\fR option, the \&\fB\-CC\fR option causes all \*(C+\-style comments inside a macro to be converted to C\-style comments. This is to prevent later use of that macro from inadvertently commenting out the remainder of the source line. .Sp The \fB\-CC\fR option is generally used to support lint comments. .IP "\fB\-traditional\-cpp\fR" 4 .IX Item "-traditional-cpp" Try to imitate the behavior of old-fashioned C preprocessors, as opposed to \s-1ISO\s0 C preprocessors. .IP "\fB\-trigraphs\fR" 4 .IX Item "-trigraphs" Process trigraph sequences. .IP "\fB\-remap\fR" 4 .IX Item "-remap" Enable special code to work around file systems which only permit very short file names, such as MS-DOS. .IP "\fB\-\-help\fR" 4 .IX Item "--help" .PD 0 .IP "\fB\-\-target\-help\fR" 4 .IX Item "--target-help" .PD Print text describing all the command line options instead of preprocessing anything. .IP "\fB\-v\fR" 4 .IX Item "-v" Verbose mode. Print out \s-1GNU\s0 \s-1CPP\s0's version number at the beginning of execution, and report the final form of the include path. .IP "\fB\-H\fR" 4 .IX Item "-H" Print the name of each header file used, in addition to other normal activities. Each name is indented to show how deep in the \&\fB#include\fR stack it is. Precompiled header files are also printed, even if they are found to be invalid; an invalid precompiled header file is printed with \fB...x\fR and a valid one with \fB...!\fR . .IP "\fB\-version\fR" 4 .IX Item "-version" .PD 0 .IP "\fB\-\-version\fR" 4 .IX Item "--version" .PD Print out \s-1GNU\s0 \s-1CPP\s0's version number. With one dash, proceed to preprocess as normal. With two dashes, exit immediately. .SH "ENVIRONMENT" .IX Header "ENVIRONMENT" This section describes the environment variables that affect how \s-1CPP\s0 operates. You can use them to specify directories or prefixes to use when searching for include files, or to control dependency output. .PP Note that you can also specify places to search using options such as \&\fB\-I\fR, and control dependency output with options like \&\fB\-M\fR. These take precedence over environment variables, which in turn take precedence over the configuration of \s-1GCC\s0. .IP "\fB\s-1CPATH\s0\fR" 4 .IX Item "CPATH" .PD 0 .IP "\fBC_INCLUDE_PATH\fR" 4 .IX Item "C_INCLUDE_PATH" .IP "\fB\s-1CPLUS_INCLUDE_PATH\s0\fR" 4 .IX Item "CPLUS_INCLUDE_PATH" .IP "\fB\s-1OBJC_INCLUDE_PATH\s0\fR" 4 .IX Item "OBJC_INCLUDE_PATH" .PD Each variable's value is a list of directories separated by a special character, much like \fB\s-1PATH\s0\fR, in which to look for header files. The special character, \f(CW\*(C`PATH_SEPARATOR\*(C'\fR, is target-dependent and determined at \s-1GCC\s0 build time. For Microsoft Windows-based targets it is a semicolon, and for almost all other targets it is a colon. .Sp \&\fB\s-1CPATH\s0\fR specifies a list of directories to be searched as if specified with \fB\-I\fR, but after any paths given with \fB\-I\fR options on the command line. This environment variable is used regardless of which language is being preprocessed. .Sp The remaining environment variables apply only when preprocessing the particular language indicated. Each specifies a list of directories to be searched as if specified with \fB\-isystem\fR, but after any paths given with \fB\-isystem\fR options on the command line. .Sp In all these variables, an empty element instructs the compiler to search its current working directory. Empty elements can appear at the beginning or end of a path. For instance, if the value of \&\fB\s-1CPATH\s0\fR is \f(CW\*(C`:/special/include\*(C'\fR, that has the same effect as \fB\-I.\ \-I/special/include\fR. .IP "\fB\s-1DEPENDENCIES_OUTPUT\s0\fR" 4 .IX Item "DEPENDENCIES_OUTPUT" If this variable is set, its value specifies how to output dependencies for Make based on the non-system header files processed by the compiler. System header files are ignored in the dependency output. .Sp The value of \fB\s-1DEPENDENCIES_OUTPUT\s0\fR can be just a file name, in which case the Make rules are written to that file, guessing the target name from the source file name. Or the value can have the form \&\fIfile\fR\fB \fR\fItarget\fR, in which case the rules are written to file \fIfile\fR using \fItarget\fR as the target name. .Sp In other words, this environment variable is equivalent to combining the options \fB\-MM\fR and \fB\-MF\fR, with an optional \fB\-MT\fR switch too. .IP "\fB\s-1SUNPRO_DEPENDENCIES\s0\fR" 4 .IX Item "SUNPRO_DEPENDENCIES" This variable is the same as \fB\s-1DEPENDENCIES_OUTPUT\s0\fR (see above), except that system header files are not ignored, so it implies \&\fB\-M\fR rather than \fB\-MM\fR. However, the dependence on the main input file is omitted. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf\-funding\fR\|(7), \&\fIgcc\fR\|(1), \fIas\fR\|(1), \fIld\fR\|(1), and the Info entries for \fIcpp\fR, \fIgcc\fR, and \&\fIbinutils\fR. .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright (c) 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. .PP Permission is granted to copy, distribute and/or modify this document under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation. A copy of the license is included in the man page \fIgfdl\fR\|(7). This manual contains no Invariant Sections. The Front-Cover Texts are (a) (see below), and the Back-Cover Texts are (b) (see below). .PP (a) The \s-1FSF\s0's Front-Cover Text is: .PP .Vb 1 \& A GNU Manual .Ve .PP (b) The \s-1FSF\s0's Back-Cover Text is: .PP .Vb 3 \& You have freedom to copy and modify this GNU Manual, like GNU \& software. Copies published by the Free Software Foundation raise \& funds for GNU development. .Ve '\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: tclsh.1,v 1.8 2003/02/13 22:03:34 kennykb Exp $ '\" '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?version? ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. The first argument is ignored and used for recording '\" the version when the .VS was added, so that the sidebars can be '\" found and removed when they reach a certain age. If another argument '\" is present, then a line break is forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b '\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. '\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out '\" # BS - start boxed text '\" # ^y = starting y location '\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. '\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. '\" # VS - start vertical sidebar '\" # ^Y = starting y location '\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. '\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. '\" # Special macro to handle page bottom: finish off current '\" # box/sidebar if in box/sidebar mode, then invoked standard '\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. '\" # DS - begin display .de DS .RS .nf .sp .. '\" # DE - end display .de DE .fi .RE .sp .. '\" # SO - start of list of standard options .de SO .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. '\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\fBoptions\\fR manual entry for details on the standard options. .. '\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH tclsh 1 "" Tcl "Tcl Applications" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME tclsh \- Simple shell containing Tcl interpreter .SH SYNOPSIS \fBtclsh\fR ?\fIfileName arg arg ...\fR? .BE .SH DESCRIPTION .PP \fBTclsh\fR is a shell-like application that reads Tcl commands from its standard input or from a file and evaluates them. If invoked with no arguments then it runs interactively, reading Tcl commands from standard input and printing command results and error messages to standard output. It runs until the \fBexit\fR command is invoked or until it reaches end-of-file on its standard input. If there exists a file \fB.tclshrc\fR (or \fBtclshrc.tcl\fR on the Windows platforms) in the home directory of the user, \fBtclsh\fR evaluates the file as a Tcl script just before reading the first command from standard input. .SH "SCRIPT FILES" .PP If \fBtclsh\fR is invoked with arguments then the first argument is the name of a script file and any additional arguments are made available to the script as variables (see below). Instead of reading commands from standard input \fBtclsh\fR will read Tcl commands from the named file; \fBtclsh\fR will exit when it reaches the end of the file. .VS 8.4 The end of the file may be marked either by the physical end of the medium, or by the character, '\\032' ('\\u001a', control-Z). If this character is present in the file, the \fBtclsh\fR application will read text up to but not including the character. An application that requires this character in the file may safely encode it as ``\\032'', ``\\x1a'', or ``\\u001a''; or may generate it by use of commands such as \fBformat\fR or \fBbinary\fR. .VE There is no automatic evaluation of \fB.tclshrc\fR when the name of a script file is presented on the \fBtclsh\fR command line, but the script file can always \fBsource\fR it if desired. .PP If you create a Tcl script in a file whose first line is .CS \fB#!/usr/local/bin/tclsh\fR .CE then you can invoke the script file directly from your shell if you mark the file as executable. This assumes that \fBtclsh\fR has been installed in the default location in /usr/local/bin; if it's installed somewhere else then you'll have to modify the above line to match. Many UNIX systems do not allow the \fB#!\fR line to exceed about 30 characters in length, so be sure that the \fBtclsh\fR executable can be accessed with a short file name. .PP An even better approach is to start your script files with the following three lines: .CS \fB#!/bin/sh # the next line restarts using tclsh \e exec tclsh "$0" "$@"\fR .CE This approach has three advantages over the approach in the previous paragraph. First, the location of the \fBtclsh\fR binary doesn't have to be hard-wired into the script: it can be anywhere in your shell search path. Second, it gets around the 30-character file name limit in the previous approach. Third, this approach will work even if \fBtclsh\fR is itself a shell script (this is done on some systems in order to handle multiple architectures or operating systems: the \fBtclsh\fR script selects one of several binaries to run). The three lines cause both \fBsh\fR and \fBtclsh\fR to process the script, but the \fBexec\fR is only executed by \fBsh\fR. \fBsh\fR processes the script first; it treats the second line as a comment and executes the third line. The \fBexec\fR statement cause the shell to stop processing and instead to start up \fBtclsh\fR to reprocess the entire script. When \fBtclsh\fR starts up, it treats all three lines as comments, since the backslash at the end of the second line causes the third line to be treated as part of the comment on the second line. .PP .VS You should note that it is also common practise to install tclsh with its version number as part of the name. This has the advantage of allowing multiple versions of Tcl to exist on the same system at once, but also the disadvantage of making it harder to write scripts that start up uniformly across different versions of Tcl. .VE .SH "VARIABLES" .PP \fBTclsh\fR sets the following Tcl variables: .TP 15 \fBargc\fR Contains a count of the number of \fIarg\fR arguments (0 if none), not including the name of the script file. .TP 15 \fBargv\fR Contains a Tcl list whose elements are the \fIarg\fR arguments, in order, or an empty string if there are no \fIarg\fR arguments. .TP 15 \fBargv0\fR Contains \fIfileName\fR if it was specified. Otherwise, contains the name by which \fBtclsh\fR was invoked. .TP 15 \fBtcl_interactive\fR Contains 1 if \fBtclsh\fR is running interactively (no \fIfileName\fR was specified and standard input is a terminal-like device), 0 otherwise. .SH PROMPTS .PP When \fBtclsh\fR is invoked interactively it normally prompts for each command with ``\fB% \fR''. You can change the prompt by setting the variables \fBtcl_prompt1\fR and \fBtcl_prompt2\fR. If variable \fBtcl_prompt1\fR exists then it must consist of a Tc