#include <sys/types.h>
#include <pwd.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>


/*
    On success, getpwnam_r() and getpwuid_r() return zero, and set *result to pwd.
    If no matching password record was found, these functions return 0 and store NULL in *result.  In case of error, an error number is returned, and NULL is stored in *result
    
    in case of too small buffer: ERANGE Insufficient buffer space supplied
*/

int main(int argc, char** argv) {
    struct passwd   pw;
    struct passwd* ppw = 0;
    const char* user = "nobody";
    size_t len = argc > 1 ? atoi(argv[1]) : 128;
    char* buffer= (char*) malloc(len);
    
    int rc = getpwnam_r(user, &pw, buffer, len, &ppw);
    
    printf("rc=%d, ppw=%p", rc, ppw);
    if ((rc == 0) && (ppw != NULL)) {
	printf(", pw_uid=%ld, pw_gid=%ld", (long) ppw->pw_uid, (long) ppw->pw_uid);
    }
    printf("\n");
    fflush(stdout);
    
    free(buffer);
    
    return rc;
}