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.Dd April 3, 2022
.Dt STRCMP 3
.Os
.Sh NAME
.Nm strcmp ,
.Nm strncmp
.Nd compare strings
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft int
.Fn strcmp "const char *s1" "const char *s2"
.Ft int
.Fn strncmp "const char *s1" "const char *s2" "size_t len"
.Sh DESCRIPTION
The
.Fn strcmp
and
.Fn strncmp
functions
lexicographically compare the null-terminated strings
.Fa s1
and
.Fa s2 .
.Pp
The
.Fn strncmp
function
compares not more than
.Fa len
characters.
Because
.Fn strncmp
is designed for comparing strings rather than binary data,
characters that appear after a
.Ql \e0
character are not compared.
.Sh RETURN VALUES
The
.Fn strcmp
and
.Fn strncmp
functions return an integer greater than, equal to, or less than 0, according
as the string
.Fa s1
is greater than, equal to, or less than the string
.Fa s2 .
The comparison is done using unsigned characters, so that
.Ql \e200
is greater than
.Ql \e0 .
.Sh SEE ALSO
.Xr bcmp 3 ,
.Xr memcmp 3 ,
.Xr strcasecmp 3 ,
.Xr strcoll 3 ,
.Xr strxfrm 3 ,
.Xr wcscmp 3
.Sh STANDARDS
The
.Fn strcmp
and
.Fn strncmp
functions
conform to
.St -isoC .
.Sh HISTORY
The
.Fn strcmp
function first appeared in the Programmer's Workbench (PWB/UNIX)
and was ported to
.At v7 ;
.Fn strncmp
first appeared in
.At v7 .