Manual Pages  — STRCMP

strcmp, strncmp – compare strings

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES SEE ALSO STANDARDS HISTORY

Standard C Library (libc, -lc)

#include <string.h>

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

int
strncmp(const char *s1, const char *s2, size_t len);

The strcmp() and strncmp() functions lexicographically compare the null-terminated strings s1 and s2.

The strncmp() function compares not more than len characters. Because strncmp() is designed for comparing strings rather than binary data, characters that appear after a ‘\0’ character are not compared.

The strcmp() and strncmp() functions return an integer greater than, equal to, or less than 0, according as the string s1 is greater than, equal to, or less than the string s2. The comparison is done using unsigned characters, so that ‘\200’ is greater than ‘\0’.

The strcmp() and strncmp() functions conform to ISO/IEC 9899:1990 ("ISO C90").

The strcmp() function first appeared in the Programmer's Workbench (PWB/UNIX) and was ported to AT&T v7 ; strncmp() first appeared in AT&T v7 .