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man:rpmatch

RPMATCH(3) Linux Programmer's Manual RPMATCH(3)

NAME

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

SYNOPSIS

     #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

DESCRIPTION

     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  environ-
     ment 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 nega-
     tive.

RETURN VALUE

     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.

ERRORS

     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 any-
     where else, but indicates a failure of the regex engine (but this  case
     is indistinguishable from that of an unrecognized value of response).

ATTRIBUTES

     For   an   explanation   of   the  terms  used  in  this  section,  see
     attributes(7).
     +----------+---------------+----------------+
     |Interface | Attribute     | Value          |
     +----------+---------------+----------------+
     |rpmatch() | Thread safety | MT-Safe locale |
     +----------+---------------+----------------+

CONFORMING TO

     rpmatch() is not required by any standard, but is available  on  a  few
     other systems.

BUGS

     The  rpmatch()  implementation  looks  at  only  the first character of
     response.  As a consequence, "nyes" returns 0, and "ynever;  not  in  a
     million  years"  returns  1.   It  would  be preferable to accept input
     strings much more strictly, for example  (using  the  extended  regular
     expression   notation  described  in  regex(7)):  ^([yY]|yes|YES)$  and
     ^([nN]|no|NO)$.

EXAMPLE

     The following program displays the results when rpmatch() is applied to
     the string given in the program's command-line argument.
     #define  _SVID_SOURCE  #include <locale.h> #include <stdlib.h> #include
     <string.h> #include <stdio.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

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

COLOPHON

     This page is part of release 4.16 of the Linux  man-pages  project.   A
     description  of  the project, information about reporting bugs, and the
     latest    version    of    this    page,    can     be     found     at
     https://www.kernel.org/doc/man-pages/.

GNU 2017-09-15 RPMATCH(3)

/data/webs/external/dokuwiki/data/pages/man/rpmatch.txt · Last modified: 2019/05/17 09:32 by 127.0.0.1

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