strcasecmp
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
strcasecmp, strncasecmp - compare two strings ignoring case
LIBRARY
Standard C library
(
libc,~
-lc)
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 byt-b-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 | M-Safe locale
|
STANDARDS
POSIX.-2008.
HISTORY
4.4BSD, POSIX.-2001.
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.-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
memcmp(3),
strcmp(3),
strcoll(3),
string(3),
strncmp(3),
wcscasecmp(3),
wcsncasecmp(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
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