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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | BUGS | EXAMPLES | SEE ALSO | COLOPHON |
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rpmatch(3) Library Functions Manual rpmatch(3)
rpmatch - determine if the answer to a question is affirmative or
negative
Standard C library (libc, -lc)
#include <stdlib.h>
int rpmatch(const char *response);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
rpmatch():
Since glibc 2.19:
_DEFAULT_SOURCE
glibc 2.19 and earlier:
_SVID_SOURCE
rpmatch() handles a user response to yes or no questions, with
support for internationalization.
response should be a null-terminated string containing a user-
supplied response, perhaps obtained with fgets(3) or getline(3).
The user's language preference is taken into account per the
environment variables LANG, LC_MESSAGES, and LC_ALL, if the
program has called setlocale(3) to effect their changes.
Regardless of the locale, responses matching ^[Yy] are always
accepted as affirmative, and those matching ^[Nn] are always
accepted as negative.
After examining response, rpmatch() returns 0 for a recognized
negative response ("no"), 1 for a recognized positive response
("yes"), and -1 when the value of response is unrecognized.
A return value of -1 may indicate either an invalid input, or
some other error. It is incorrect to only test if the return
value is nonzero.
rpmatch() can fail for any of the reasons that regcomp(3) or
regexec(3) can fail; the cause of the error is not available from
errno or anywhere else, but indicates a failure of the regex
engine (but this case is indistinguishable from that of an
unrecognized value of response).
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────┬───────────────┬────────────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────┼───────────────┼────────────────┤
│ rpmatch() │ Thread safety │ MT-Safe locale │
└──────────────────────────────┴───────────────┴────────────────┘
None.
GNU, FreeBSD, AIX.
The YESEXPR and NOEXPR of some locales (including "C") only
inspect the first character of the response. This can mean that
"yno" et al. resolve to 1. This is an unfortunate historical
side-effect which should be fixed in time with proper
localisation, and should not deter from rpmatch() being the
proper way to distinguish between binary answers.
The following program displays the results when rpmatch() is
applied to the string given in the program's command-line
argument.
#define _DEFAULT_SOURCE
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main(int argc, char *argv[])
{
if (argc != 2 || strcmp(argv[1], "--help") == 0) {
fprintf(stderr, "%s response\n", argv[0]);
exit(EXIT_FAILURE);
}
setlocale(LC_ALL, "");
printf("rpmatch() returns: %d\n", rpmatch(argv[1]));
exit(EXIT_SUCCESS);
}
fgets(3), getline(3), nl_langinfo(3), regcomp(3), setlocale(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.9.1 2024-06-15 rpmatch(3)
Pages that refer to this page: setlocale(3), locale(7)
Copyright and license for this manual page
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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