Header File 

mem.h, string.h  

Category 

Memory and String Manipulation Routines, Inline Routines 

Prototype 

void *memset(void *s, int c, size_t n); 

void *_wmemset(void *s, int c, size_t n); 

Description 

Sets n bytes of a block of memory to byte c. 

memset sets the first n bytes of the array s to the character c. 

Return Value 

memset returns s. 

Example  

#include <string.h>
#include <stdio.h>
#include <mem.h>
int main(void)
{
    char buffer[] = "Hello world\n";
    printf("Buffer before memset: %s\n", buffer);
    memset(buffer, '*', strlen(buffer) - 1);
    printf("Buffer after memset:  %s\n", buffer);
    return 0;
}

Portability