NAME

strcmp - strings compare

LIBRARY

Standard C library (libc, -lc)

SYNOPSIS

#include <string.h>

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

DESCRIPTION

The strcmp() function compares the two strings s1 and s2, as if by calling memcmp(3).

It is equivalent to

memcmp(s1, s2, MIN(strlen(s1),strlen(s2))+1)

RETURN VALUE

See memcmp(3).

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
strcmp ()	Thread safety	MT-Safe

STANDARDS

C11, POSIX.1-2008.

HISTORY

POSIX.1-2001, C89, SVr4, 4.3BSD.

CAVEATS

The locale is not taken into account (for a locale-aware comparison, see strcoll(3)).

EXAMPLES

The program below can be used to demonstrate the operation of strcmp().

$ ./strcmp ABC ABC;
<str1> and <str2> are equal
$ ./strcmp ABC AB;      # 'C' is ASCII 67; 'C' - '\0' = 67
<str1> is greater than <str2> (67)
$ ./strcmp ABA ABZ;     # 'A' is ASCII 65; 'Z' is ASCII 90
<str1> is less than <str2> (-25)
$ ./strcmp ABJ ABC;
<str1> is greater than <str2> (7)
$ ./strcmp $'\201' A;   # 0201 - 0101 = 0100 (or 64 decimal)
<str1> is greater than <str2> (64)

The last example uses bash(1)-specific syntax to produce a string containing an 8-bit ASCII code; the result demonstrates that the string comparison uses unsigned characters.

Program source

// strcmp.c
// Licensed under GNU General Public License v2 or later.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int
main(int argc, char *argv[])
{
    int res;
    if (argc != 3) {
        fprintf(stderr, "Usage: %s <str1> <str2>\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    res = strcmp(argv[1], argv[2]);
    if (res == 0) {
        printf("<str1> and <str2> are equal");
        printf("\n");
    } else if (res < 0) {
        printf("<str1> is less than <str2> (%d)\n", res);
    } else {
        printf("<str1> is greater than <str2> (%d)\n", res);
    }
    exit(EXIT_SUCCESS);
}