NAME
strcasecmp,
    strcasecmp_l, strncasecmp,
    strncasecmp_l —
    compare strings, ignoring
  case
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 len);
int
  
  strncasecmp_l(const char *s1,
    const char *s2, size_t len,
    locale_t locale);
DESCRIPTION
These 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’.
strncasecmp()
    and
    strncasecmp_l()
    compare at most len characters.
On OpenBSD, these functions always use the C locale and ignore the global locale, the thread-specific locale, and the locale argument.
ENVIRONMENT
On other operating systems, the behaviour of
    strcasecmp() and
    strncasecmp() may depend on the
    LC_CTYPE
    locale(1).
SEE ALSO
STANDARDS
These functions conform to IEEE Std 1003.1-2008 (“POSIX.1”).
HISTORY
The strcasecmp() and
    strncasecmp() functions have been available since
    4.3BSD-Tahoe, and
    strcasecmp_l() and
    strncasecmp_l() since OpenBSD
    6.2.