/*
 *  File chk_memset.c -- A test of memset() 
 *
 *    For some number N > 8, set the first N chars of a buffer
 *    with a char > 0x7F  (in an unsigned sense)
 *
 *    Check whether unanticipated sign extension in the memset()
 *    function has overwritten the first few chars of the buffer.
 *
 *  Run the test using:
 *      % cc compiler_options_of_your_choice chk_memset.c
 *      % a.out
 *
 *  Failures have been reported on 
 *     some SGI Irix 6.2 systems with     cc -n32 chk_memset.c
 * 
 */
 
#include <string.h>
#include <stdio.h>

#ifndef N
#define N 100
#endif
size_t n = N;
signed char buf[N*2];
signed char set_char = -0x80;
 
void assign ( signed char set_char ) {
    int i;
    for(i=0; i<n; i++) {
	buf[i] = set_char;
        }
}

int check ( signed char set_char ) {
    int fails = 0;
    int i;
    for(i=0; i<n&&fails==0; i++) {
       if( buf[i] != set_char) {
           printf("  buf[%d] = 0x%x != 0x%x \n", i, buf[i], set_char);
           fails++;
        }
    }
    return fails;
}

int main() {
 
    int fail = 0;

    /* simple assignment test
     * 
     * just make sure that the "check" routine
     * works as it is supposed to
     *
     */
    assign(set_char);
    if( check(set_char) == 0) 
       printf("simple assignment test passed\n");
    else {
       printf("simple assignment test failed\n");
       fail++;
    }

    assign(0);


    printf("Calling memset(buf, set_char, n) with set_char=0x%x and n=%d\n",
           set_char, n); 

    memset(buf, set_char, n);
    if( check(set_char) == 0) 
       printf("memset() test passed\n\n");
    else {
       printf("memset() test failed\n\n");
       fail++;
    }

    return fail;
}