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diff --git a/man3/getsubopt.3 b/man3/getsubopt.3 new file mode 100644 index 0000000..8cbccb0 --- /dev/null +++ b/man3/getsubopt.3 @@ -0,0 +1,252 @@ +'\" t +.\" Copyright (C) 2007 Michael Kerrisk <mtk.manpages@gmail.com> +.\" and Copyright (C) 2007 Justin Pryzby <pryzbyj@justinpryzby.com> +.\" +.\" %%%LICENSE_START(PERMISSIVE_MISC) +.\" Permission is hereby granted, free of charge, to any person obtaining +.\" a copy of this software and associated documentation files (the +.\" "Software"), to deal in the Software without restriction, including +.\" without limitation the rights to use, copy, modify, merge, publish, +.\" distribute, sublicense, and/or sell copies of the Software, and to +.\" permit persons to whom the Software is furnished to do so, subject to +.\" the following conditions: +.\" +.\" The above copyright notice and this permission notice shall be +.\" included in all copies or substantial portions of the Software. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +.\" EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +.\" IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +.\" CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, +.\" TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE +.\" SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +.\" %%%LICENSE_END +.\" +.TH getsubopt 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +getsubopt \- parse suboption arguments from a string +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdlib.h> +.PP +.BI "int getsubopt(char **restrict " optionp ", char *const *restrict " tokens , +.BI " char **restrict " valuep ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR getsubopt (): +.nf + _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L +.fi +.SH DESCRIPTION +.BR getsubopt () +parses the list of comma-separated suboptions provided in +.IR optionp . +(Such a suboption list is typically produced when +.BR getopt (3) +is used to parse a command line; +see for example the \fI\-o\fP option of +.BR mount (8).) +Each suboption may include an associated value, +which is separated from the suboption name by an equal sign. +The following is an example of the kind of string +that might be passed in +.IR optionp : +.PP +.in +4n +.EX +.B ro,name=xyz +.EE +.in +.PP +The +.I tokens +argument is a pointer to a NULL-terminated array of pointers to the tokens that +.BR getsubopt () +will look for in +.IR optionp . +The tokens should be distinct, null-terminated strings containing at +least one character, with no embedded equal signs or commas. +.PP +Each call to +.BR getsubopt () +returns information about the next unprocessed suboption in +.IR optionp . +The first equal sign in a suboption (if any) is interpreted as a +separator between the name and the value of that suboption. +The value extends to the next comma, +or (for the last suboption) to the end of the string. +If the name of the suboption matches a known name from +.IR tokens , +and a value string was found, +.BR getsubopt () +sets +.I *valuep +to the address of that string. +The first comma in +.I optionp +is overwritten with a null byte, so +.I *valuep +is precisely the "value string" for that suboption. +.PP +If the suboption is recognized, but no value string was found, +.I *valuep +is set to NULL. +.PP +When +.BR getsubopt () +returns, +.I optionp +points to the next suboption, +or to the null byte (\[aq]\e0\[aq]) at the end of the +string if the last suboption was just processed. +.SH RETURN VALUE +If the first suboption in +.I optionp +is recognized, +.BR getsubopt () +returns the index of the matching suboption element in +.IR tokens . +Otherwise, \-1 is returned and +.I *valuep +is the entire +.IB name [= value ] +string. +.PP +Since +.I *optionp +is changed, the first suboption before the call to +.BR getsubopt () +is not (necessarily) the same as the first suboption after +.BR getsubopt (). +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR getsubopt () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001. +.SH NOTES +Since +.BR getsubopt () +overwrites any commas it finds in the string +.IR *optionp , +that string must be writable; it cannot be a string constant. +.SH EXAMPLES +The following program expects suboptions following a "\-o" option. +.PP +.\" SRC BEGIN (getsubopt.c) +.EX +#define _XOPEN_SOURCE 500 +#include <stdio.h> +#include <stdlib.h> +\& +#include <assert.h> +\& +int +main(int argc, char *argv[]) +{ + enum { + RO_OPT = 0, + RW_OPT, + NAME_OPT + }; + char *const token[] = { + [RO_OPT] = "ro", + [RW_OPT] = "rw", + [NAME_OPT] = "name", + NULL + }; + char *subopts; + char *value; + int opt; +\& + int readonly = 0; + int readwrite = 0; + char *name = NULL; + int errfnd = 0; +\& + while ((opt = getopt(argc, argv, "o:")) != \-1) { + switch (opt) { + case \[aq]o\[aq]: + subopts = optarg; + while (*subopts != \[aq]\e0\[aq] && !errfnd) { +\& + switch (getsubopt(&subopts, token, &value)) { + case RO_OPT: + readonly = 1; + break; +\& + case RW_OPT: + readwrite = 1; + break; +\& + case NAME_OPT: + if (value == NULL) { + fprintf(stderr, + "Missing value for suboption \[aq]%s\[aq]\en", + token[NAME_OPT]); + errfnd = 1; + continue; + } +\& + name = value; + break; +\& + default: + fprintf(stderr, + "No match found for token: /%s/\en", value); + errfnd = 1; + break; + } + } + if (readwrite && readonly) { + fprintf(stderr, + "Only one of \[aq]%s\[aq] and \[aq]%s\[aq] can be specified\en", + token[RO_OPT], token[RW_OPT]); + errfnd = 1; + } + break; +\& + default: + errfnd = 1; + } + } +\& + if (errfnd || argc == 1) { + fprintf(stderr, "\enUsage: %s \-o <suboptstring>\en", argv[0]); + fprintf(stderr, + "suboptions are \[aq]ro\[aq], \[aq]rw\[aq], and \[aq]name=<value>\[aq]\en"); + exit(EXIT_FAILURE); + } +\& + /* Remainder of program... */ +\& + exit(EXIT_SUCCESS); +} +.EE +.\" SRC END +.SH SEE ALSO +.BR getopt (3) |