strcasecmp (3)
Leading comments
Copyright 1993 David Metcalfe (david@prism.demon.co.uk) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Sin...
NAME
strcasecmp, strncasecmp - compare two strings ignoring caseSYNOPSIS
#include <strings.h> int strcasecmp(const char *s1, const char *s2); int strncasecmp(const char *s1, const char *s2, size_t n);
DESCRIPTION
The strcasecmp() function performs a byte-by-byte comparison of the strings s1 and s2, ignoring the case of the characters. It returns an integer less than, equal to, or greater than zero if s1 is found, respectively, to be less than, to match, or be greater than s2.The strncasecmp() function is similar, except it compares only the first n bytes of s1.
RETURN VALUE
The strcasecmp() and strncasecmp() functions return an integer less than, equal to, or greater than zero if s1 (or the first n bytes thereof) is found, respectively, to be less than, to match, or be greater than s2.ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
| strcasecmp(), strncasecmp() | Thread safety | MT-Safe locale |
CONFORMING TO
4.4BSD, POSIX.1-2001, POSIX.1-2008.NOTES
The strcasecmp() and strncasecmp() functions first appeared in 4.4BSD, where they were declared in <string.h>. Thus, for reasons of historical compatibility, the glibc <string.h> header file also declares these functions, if the _DEFAULT_SOURCE (or, in glibc 2.19 and earlier, _BSD_SOURCE) feature test macro is defined.The POSIX.1-2008 standard says of these functions:
- When the LC_CTYPE category of the locale being used is from the POSIX locale, these functions shall behave as if the strings had been converted to lowercase and then a byte comparison performed. Otherwise, the results are unspecified.