NAME

       strcasecmp, strncasecmp - compare two strings ignoring case

SYNOPSIS

       #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 that it compares no more than n bytes of  s1
       and s2.

RETURN VALUE

       The  strcasecmp()  and  strncasecmp()  functions return an integer less than, equal to, or
       greater than zero if s1 is, after ignoring case, found to be less than, to  match,  or  be
       greater than s2, respectively.

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.

SEE ALSO

       bcmp(3),  memcmp(3),  strcmp(3),   strcoll(3),   string(3),   strncmp(3),   wcscasecmp(3),
       wcsncasecmp(3)

COLOPHON

       This  page  is  part of release 5.13 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.

                                            2021-03-22                              STRCASECMP(3)