strcasecmp man page

Prolog

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strcasecmp, strcasecmp_l, strncasecmp, strncasecmp_l — case-insensitive string comparisons

Synopsis

#include <strings.h>

int strcasecmp(const char *s1, const char *s2);
int strcasecmp_l(const char *s1, const char *s2,
    locale_t locale);
int strncasecmp(const char *s1, const char *s2, size_t n);
int strncasecmp_l(const char *s1, const char *s2,
    size_t n, locale_t locale);

Description

The strcasecmp() and strcasecmp_l() functions shall compare, while ignoring differences in case, the string pointed to by s1 to the string pointed to by s2. The strncasecmp() and strncasecmp_l() functions shall compare, while ignoring differences in case, not more than n bytes from the string pointed to by s1 to the string pointed to by s2.

The strcasecmp() and strncasecmp() functions use the current locale to determine the case of the characters.

The strcasecmp_l() and strncasecmp_l() functions use the locale represented by locale to determine the case of the characters.

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.

The behavior is undefined if the locale argument to strcasecmp_l() or strncasecmp_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.

Return Value

Upon completion, strcasecmp() and strcasecmp_l() shall return an integer greater than, equal to, or less than 0, if the string pointed to by s1 is, ignoring case, greater than, equal to, or less than the string pointed to by s2, respectively.

Upon successful completion, strncasecmp() and strncasecmp_l() shall return an integer greater than, equal to, or less than 0, if the possibly null-terminated array pointed to by s1 is, ignoring case, greater than, equal to, or less than the possibly null-terminated array pointed to by s2, respectively.

Errors

No errors are defined.

The following sections are informative.

See Also

wcscasecmp()

The Base Definitions volume of POSIX.1‐2008, <strings.h>

Info

2013 IEEE/The Open Group POSIX Programmer's Manual