strncmp3
Nonstrings compare
Usage
#include <string.h> // see memory.h(3head)
int strncmp(const char s1[], const char s2[], size_t n);
Library
Standard C library (libc, -lc)
Overview
The strncmp() function is similar to strcmp(3), except it compares only the first (at most) n bytes of s1 and s2.
It is equivalent to
memcmp(s1, s2, MIN(MIN(strnlen(s1,n),strnlen(s2,n))+1, n))
Return value
See memcmp(3).
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| strncmp() | Thread safety | MT-Safe |
Examples
The program below can be used to demonstrate the operation of strncmp().
$ ./strncmp ABC AB 3; <strn1> is greater than <strn2> (67) $ ./strncmp ABC AB 2; <strn1> and <str2> are equal in the first 2 bytes
Program source
// strncmp.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 != 4) {
fprintf(stderr, "Usage: %s <strn1> <strn2> <n>\n", argv[0]);
exit(EXIT_FAILURE);
}
res = strncmp(argv[1], argv[2], atoi(argv[3]));
if (res == 0) {
printf("<strn1> and <strn2> are equal");
printf(" in the first %d bytes\n", atoi(argv[3]));
printf("\n");
} else if (res < 0) {
printf("<strn1> is less than <strn2> (%d)\n", res);
} else {
printf("<strn1> is greater than <strn2> (%d)\n", res);
}
exit(EXIT_SUCCESS);
}
Releases
19 releases since Debian 1.1 (Buzz); the text changed 13 times.