strncasecmp(3) — Linux manual page


STRCASECMP(3)             Linux Programmer's Manual            STRCASECMP(3)

NAME         top

       strcasecmp, strncasecmp - compare two strings ignoring case

SYNOPSIS         top

       #include <strings.h>

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

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

DESCRIPTION         top

       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         top

       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         top

       For an explanation of the terms used in this section, see

       │Interface                   Attribute     Value          │
       │strcasecmp(), strncasecmp() │ Thread safety │ MT-Safe locale │

CONFORMING TO         top

       4.4BSD, POSIX.1-2001, POSIX.1-2008.

NOTES         top

       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         top

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

COLOPHON         top

       This page is part of release 5.08 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

                                 2017-09-15                    STRCASECMP(3)

Pages that refer to this page: bcmp(3)memcmp(3)strcmp(3)string(3)strncmp(3)wcsncasecmp(3)