STRCASECMP(3) Library Functions Manual STRCASECMP(3)

strcasecmp, strncasecmp
compare strings, ignoring case

Standard C Library (libc, -lc)

#include <strings.h>

int
strcasecmp(const char *s1, const char *s2);

int
strncasecmp(const char *s1, const char *s2, size_t len);

The strcasecmp() and strncasecmp() functions compare the nul-terminated strings s1 and s2 and return an integer greater than, equal to, or less than 0, according to whether s1 is lexicographically greater than, equal to, or less than s2 after translation of each corresponding character to lower-case. The strings themselves are not modified. The comparison is done using unsigned characters, so that ‘\200’ is greater than ‘\0’.

The strncasecmp() function compares at most len characters.

bcmp(3), memcmp(3), strcmp(3), strcoll(3), strxfrm(3)

The strcasecmp() and strncasecmp() functions conform to IEEE Std 1003.1-2001 (“POSIX.1”).

The strcasecmp() and strncasecmp() functions first appeared in 4.4BSD.

If len is 0 strncasecmp() always returns 0.
July 11, 2016 NetBSD 9.2