Linux Man Page Viewer
The following form allows you to view linux man pages.
int rpmatch(const char *response);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
rpmatch() handles a user response to yes or no questions, with support
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-
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
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).
rpmatch() is not required by any standard, but is available on a few
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
fprintf(stderr, "%s response\n", argv);
printf("rpmatch() returns: %d\n", rpmatch(argv));
fgets(3), getline(3), nl_langinfo(3), regcomp(3), setlocale(3)
GNU 2007-07-26 RPMATCH(3)