1 .\" Copyright (C) 2006 Justin Pryzby <pryzbyj@justinpryzby.com>
3 .\" %%%LICENSE_START(PERMISSIVE_MISC)
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25 .\" glibc manual and source
27 .\" 2006-05-19, mtk, various edits and example program
29 .TH RPMATCH 3 2021-03-22 "GNU" "Linux Programmer's Manual"
31 rpmatch \- determine if the answer to a question is affirmative or negative
34 .B #include <stdlib.h>
36 .BI "int rpmatch(const char *" response );
40 Feature Test Macro Requirements for glibc (see
41 .BR feature_test_macros (7)):
48 Glibc 2.19 and earlier:
53 handles a user response to yes or no questions, with
54 support for internationalization.
57 should be a null-terminated string containing a
58 user-supplied response, perhaps obtained with
63 The user's language preference is taken into account per the
69 if the program has called
71 to effect their changes.
73 Regardless of the locale, responses matching
75 are always accepted as affirmative, and those matching
77 are always accepted as negative.
82 returns 0 for a recognized negative response ("no"), 1
83 for a recognized positive response ("yes"), and \-1 when the value
88 A return value of \-1 may indicate either an invalid input, or some
90 It is incorrect to only test if the return value is nonzero.
93 can fail for any of the reasons that
97 can fail; the cause of the error
100 or anywhere else, but indicates a
101 failure of the regex engine (but this case is indistinguishable from
102 that of an unrecognized value of
105 For an explanation of the terms used in this section, see
113 Interface Attribute Value
116 T} Thread safety MT-Safe locale
123 is not required by any standard, but
124 is available on a few other systems.
125 .\" It is available on at least AIX 5.1 and FreeBSD 6.0.
129 implementation looks at only the first character
132 As a consequence, "nyes" returns 0, and
133 "ynever; not in a million years" returns 1.
134 It would be preferable to accept input strings much more
135 strictly, for example (using the extended regular
136 expression notation described in
138 .B \(ha([yY]|yes|YES)$
140 .BR \(ha([nN]|no|NO)$ .
142 The following program displays the results when
144 is applied to the string given in the program's command-line argument.
154 main(int argc, char *argv[])
156 if (argc != 2 || strcmp(argv[1], "\-\-help") == 0) {
157 fprintf(stderr, "%s response\en", argv[0]);
161 setlocale(LC_ALL, "");
162 printf("rpmatch() returns: %d\en", rpmatch(argv[1]));