gcc: Compilation Warning: incompatible implicit declaration of built-in function `bzero’

       bzero - write zero-valued bytes

int main(int argc, char*argv[]){
    void *s;
    size_t n;
bzero(s,n);
    return 0;
}

$ gcc bzero.c

bzero.c: In function ‘main’:
bzero.c:4: error: ‘size_t’ undeclared (first use in this function)
bzero.c:4: error: (Each undeclared identifier is reported only once
bzero.c:4: error: for each function it appears in.)
bzero.c:4: error: expected ‘;’ before ‘n’
bzero.c:5: warning: incompatible implicit declaration of built-in function ‘bzero’
bzero.c:5: error: ‘n’ undeclared (first use in this function)

#include <strings.h>

int main(int argc, char*argv[]){
    void *s;
    size_t n;
bzero(s,n);
    return 0;
}

$ gcc bzero.c