strcasecmp(3)

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

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   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/.

                              2016-07-17                     STRCASECMP(3)

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