Compare the contents of two buffers.
Include
<string.h>
Prototype
int memcmp(const void *s1, const void *s2, size_t
n);
Arguments
s1
s2
n
Return Value
Returns a positive number if s1
is greater than
s2
, zero if s1
is equal to s2
or
a negative number if s1
is less than s2
.
Remarks
This function compares the first n
characters in
s1
to the first n
characters in
s2
and returns a value indicating whether the buffers are less
than, equal to or greater than each other.
Example
#include <string.h>
#include <stdio.h>
int main(void)
{
char buf1[50] = "Where is the time?";
char buf2[50] = "Where did they go?";
char buf3[50] = "Why?";
int res;
printf("buf1 : %s\n", buf1);
printf("buf2 : %s\n", buf2);
printf("buf3 : %s\n\n", buf3);
res = memcmp(buf1, buf2, 6);
if (res < 0)
printf("buf1 comes before buf2\n");
else if (res == 0)
printf("6 characters of buf1 and buf2 "
"are equal\n");
else
printf("buf2 comes before buf1\n");
printf("\n");
res = memcmp(buf1, buf2, 20);
if (res < 0)
printf("buf1 comes before buf2\n");
else if (res == 0)
printf("20 characters of buf1 and buf2 "
"are equal\n");
else
printf("buf2 comes before buf1\n");
printf("\n");
res = memcmp(buf1, buf3, 20);
if (res < 0)
printf("buf1 comes before buf3\n");
else if (res == 0)
printf("20 characters of buf1 and buf3 "
"are equal\n");
else
printf("buf3 comes before buf1\n");
}
Example Output
buf1 : Where is the time?
buf2 : Where did they go?
buf3 : Why?
6 characters of buf1 and buf2 are equal
buf2 comes before buf1
buf1 comes before buf3