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diff --git a/man-pages-posix-2013/man3p/getopt.3p b/man-pages-posix-2013/man3p/getopt.3p new file mode 100644 index 0000000..4abec74 --- /dev/null +++ b/man-pages-posix-2013/man3p/getopt.3p @@ -0,0 +1,445 @@ +'\" et +.TH GETOPT "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. + +.SH NAME +getopt, +optarg, +opterr, +optind, +optopt +\(em command option parsing +.SH SYNOPSIS +.LP +.nf +#include <unistd.h> +.P +int getopt(int \fIargc\fP, char * const \fIargv\fP[], const char *\fIoptstring\fP); +extern char *optarg; +extern int opterr, optind, optopt; +.fi +.SH DESCRIPTION +The +\fIgetopt\fR() +function is a command-line parser that shall follow Utility Syntax +Guidelines 3, 4, 5, 6, 7, 9, and 10 in the Base Definitions volume of POSIX.1\(hy2008, +.IR "Section 12.2" ", " "Utility Syntax Guidelines". +.P +The parameters +.IR argc +and +.IR argv +are the argument count and argument array as passed to +\fImain\fR() +(see +\fIexec\fR()). +The argument +.IR optstring +is a string of recognized option characters; if a character is followed +by a +<colon>, +the option takes an argument. All option characters allowed by Utility +Syntax Guideline 3 are allowed in +.IR optstring . +The implementation may accept other characters as an extension. +.P +The variable +.IR optind +is the index of the next element of the +.IR argv [\^] +vector to be processed. It shall be initialized to 1 by the system, and +\fIgetopt\fR() +shall update it when it finishes with each element of +.IR argv [\|]. +If the application sets +.IR optind +to zero before calling +\fIgetopt\fR(), +the behavior is unspecified. When an element of +.IR argv [\|] +contains multiple option characters, it is unspecified how +\fIgetopt\fR() +determines which options have already been processed. +.P +The +\fIgetopt\fR() +function shall return the next option character (if one is found) from +.IR argv +that matches a character in +.IR optstring , +if there is one that matches. If the option takes an argument, +\fIgetopt\fR() +shall set the variable +.IR optarg +to point to the option-argument as follows: +.IP " 1." 4 +If the option was the last character in the string pointed to by an +element of +.IR argv , +then +.IR optarg +shall contain the next element of +.IR argv , +and +.IR optind +shall be incremented by 2. If the resulting value of +.IR optind +is greater than +.IR argc , +this indicates a missing option-argument, and +\fIgetopt\fR() +shall return an error indication. +.IP " 2." 4 +Otherwise, +.IR optarg +shall point to the string following the option character in that +element of +.IR argv , +and +.IR optind +shall be incremented by 1. +.P +If, when +\fIgetopt\fR() +is called: +.sp +.RS 4 +.nf +\fB + \fIargv\fP[optind] \fRis a null pointer\fP +*\fIargv\fP[optind] \fRis not the character\fP \(mi + \fIargv\fP[optind] \fRpoints to the string\fP "\(mi" +.fi \fR +.P +.RE +.P +\fIgetopt\fR() +shall return \(mi1 without changing +.IR optind . +If: +.sp +.RS 4 +.nf +\fB +\fIargv\fP[optind] \fRpoints to the string\fP "\(mi\|\(mi" +.fi \fR +.P +.RE +.P +\fIgetopt\fR() +shall return \(mi1 after incrementing +.IR optind . +.P +If +\fIgetopt\fR() +encounters an option character that is not contained in +.IR optstring , +it shall return the +<question-mark> +(\c +.BR '?' ) +character. If it detects a missing option-argument, it shall return the +<colon> +character (\c +.BR ':' ) +if the first character of +.IR optstring +was a +<colon>, +or a +<question-mark> +character (\c +.BR '?' ) +otherwise. In either case, +\fIgetopt\fR() +shall set the variable +.IR optopt +to the option character that caused the error. If the application has +not set the variable +.IR opterr +to 0 and the first character of +.IR optstring +is not a +<colon>, +\fIgetopt\fR() +shall also print a diagnostic message to +.IR stderr +in the format specified for the +.IR getopts +utility. +.P +The +\fIgetopt\fR() +function need not be thread-safe. +.SH "RETURN VALUE" +The +\fIgetopt\fR() +function shall return the next option character specified on the command +line. +.P +A +<colon> +(\c +.BR ':' ) +shall be returned if +\fIgetopt\fR() +detects a missing argument and the first character of +.IR optstring +was a +<colon> +(\c +.BR ':' ). +.P +A +<question-mark> +(\c +.BR '?' ) +shall be returned if +\fIgetopt\fR() +encounters an option character not in +.IR optstring +or detects a missing argument and the first character of +.IR optstring +was not a +<colon> +(\c +.BR ':' ). +.P +Otherwise, +\fIgetopt\fR() +shall return \(mi1 when all command line options are parsed. +.SH ERRORS +If the application has not set the variable +.IR opterr +to 0, the first character of +.IR optstring +is not a +<colon>, +and a write error occurs while +\fIgetopt\fR() +is printing a diagnostic message to +.IR stderr , +then the error indicator for +.IR stderr +shall be set; but +\fIgetopt\fR() +shall still succeed and the value of +.IR errno +after +\fIgetopt\fR() +is unspecified. +.LP +.IR "The following sections are informative." +.SH EXAMPLES +.SS "Parsing Command Line Options" +.P +The following code fragment shows how you might process the arguments +for a utility that can take the mutually-exclusive options +.IR a +and +.IR b +and the options +.IR f +and +.IR o , +both of which require arguments: +.sp +.RS 4 +.nf +\fB +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +.P +int +main(int argc, char *argv[ ]) +{ + int c; + int bflg = 0, aflg = 0, errflg = 0; + char *ifile; + char *ofile; + . . . + while ((c = getopt(argc, argv, ":abf:o:")) != -1) { + switch(c) { + case 'a': + if (bflg) + errflg++; + else + aflg++; + break; + case 'b': + if (aflg) + errflg++; + else + bflg++; + break; + case 'f': + ifile = optarg; + break; + case 'o': + ofile = optarg; + break; + case ':': /* -f or -o without operand */ + fprintf(stderr, + "Option -%c requires an operand\en", optopt); + errflg++; + break; + case '?': + fprintf(stderr, + "Unrecognized option: '-%c'\en", optopt); + errflg++; + } + } + if (errflg) { + fprintf(stderr, "usage: . . . "); + exit(2); + } + for ( ; optind < argc; optind++) { + if (access(argv[optind], R_OK)) { + . . . +} +.fi \fR +.P +.RE +.P +This code accepts any of the following as equivalent: +.sp +.RS 4 +.nf +\fB +cmd \(miao arg path path +cmd \(mia \(mio arg path path +cmd \(mio arg \(mia path path +cmd \(mia \(mio arg \(mi\|\(mi path path +cmd \(mia \(mioarg path path +cmd \(miaoarg path path +.fi \fR +.P +.RE +.SS "Selecting Options from the Command Line" +.P +The following example selects the type of database routines the user +wants to use based on the +.IR Options +argument. +.sp +.RS 4 +.nf +\fB +#include <unistd.h> +#include <string.h> +\&... +const char *Options = "hdbtl"; +\&... +int dbtype, c; +char *st; +\&... +dbtype = 0; +while ((c = getopt(argc, argv, Options)) != \(mi1) { + if ((st = strchr(Options, c)) != NULL) { + dbtype = st - Options; + break; + } +} +.fi \fR +.P +.RE +.SH "APPLICATION USAGE" +The +\fIgetopt\fR() +function is only required to support option characters included in +Utility Syntax Guideline 3. Many historical implementations of +\fIgetopt\fR() +support other characters as options. This is an allowed extension, but +applications that use extensions are not maximally portable. Note that +support for multi-byte option characters is only possible when such +characters can be represented as type +.BR int . +.P +While +.IR ferror ( stderr ) +may be used to detect failures to write a diagnostic to +.IR stderr +when +\fIgetopt\fR() +returns +.BR '?' , +the value of +.IR errno +is unspecified in such a condition. Applications desiring more control +over handling write failures should set +.IR opterr +to 0 and independently perform output to +.IR stderr , +rather than relying on +\fIgetopt\fR() +to do the output. +.SH RATIONALE +The +.IR optopt +variable represents historical practice and allows the application to +obtain the identity of the invalid option. +.P +The description has been written to make it clear that +\fIgetopt\fR(), +like the +.IR getopts +utility, deals with option-arguments whether separated from the option +by +<blank> +characters or not. Note that the requirements on +\fIgetopt\fR() +and +.IR getopts +are more stringent than the Utility Syntax Guidelines. +.P +The +\fIgetopt\fR() +function shall return \(mi1, rather than EOF, so that +.IR <stdio.h> +is not required. +.P +The special significance of a +<colon> +as the first character of +.IR optstring +makes +\fIgetopt\fR() +consistent with the +.IR getopts +utility. It allows an application to make a distinction between a +missing argument and an incorrect option letter without having to +examine the option letter. It is true that a missing argument can only +be detected in one case, but that is a case that has to be considered. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "\fIexec\fR\^" +.P +The Base Definitions volume of POSIX.1\(hy2008, +.IR "Section 12.2" ", " "Utility Syntax Guidelines", +.IR "\fB<unistd.h>\fP" +.P +The Shell and Utilities volume of POSIX.1\(hy2008, +.IR "\fIgetopts\fR\^" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, Copyright (C) 2013 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.unix.org/online.html . + +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |