Movatterモバイル変換

rpmatch(3) — Linux manual page

rpmatch(3)               Library Functions Manualrpmatch(3)

NAME        top

       rpmatch - determine if the answer to a question is affirmative or       negative

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#include <stdlib.h>int rpmatch(const char *response);   Feature Test Macro Requirements for glibc (seefeature_test_macros(7)):rpmatch():           Since glibc 2.19:               _DEFAULT_SOURCE           glibc 2.19 and earlier:               _SVID_SOURCE

DESCRIPTION        top

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 withfgets(3) orgetline(3).       The user's language preference is taken into account per the       environment variablesLANG,LC_MESSAGES, andLC_ALL, if the       program has calledsetlocale(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.

RETURN VALUE        top

       After examiningresponse,rpmatch() returns 0 for a recognized       negative response ("no"), 1 for a recognized positive response       ("yes"), and -1 when the value ofresponse is unrecognized.

ERRORS        top

       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 thatregcomp(3) orregexec(3) can fail; the error is not available fromerrno or       anywhere else, but indicates a failure of the regex engine (but       this case is indistinguishable from that of an unrecognized value       ofresponse).

ATTRIBUTES        top

       For an explanation of the terms used in this section, seeattributes(7).       ┌───────────────────────────────┬───────────────┬────────────────┐       │Interface│Attribute│Value│       ├───────────────────────────────┼───────────────┼────────────────┤       │rpmatch()                     │ Thread safety │ MT-Safe locale │       └───────────────────────────────┴───────────────┴────────────────┘

STANDARDS        top

       None.

HISTORY        top

       GNU, FreeBSD, AIX.

BUGS        top

       TheYESEXPRandNOEXPRof some locales (including "C") only       inspect the first character of theresponse.  This can mean that       "yno" et al. resolve to1.  This is an unfortunate historical       side-effect which should be fixed in time with proper       localisation, and should not deter fromrpmatch() being the proper       way to distinguish between binary answers.

EXAMPLES        top

       The following program displays the results whenrpmatch() 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);       }

SEE ALSO        top

fgets(3),getline(3),nl_langinfo(3),regcomp(3),setlocale(3)

COLOPHON        top

       This page is part of theman-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-6.15.tar.gz       fetched from       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on       2025-08-11.  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 isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-17rpmatch(3)

Pages that refer to this page:setlocale(3), locale(7)

Copyright and license for this manual page

HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH.