argv0-test/src/parent.c

#include <stdio.h>
#include <unistd.h>
#include <string.h>

int
main(int argc, char **argv, char **envp)
{
    int ret = 0;
    char *arr = NULL;
    char **ptr = 
#ifdef PTR_TO_NULL
        &arr;
    printf("%s: using &NULL as argv...\n", argv[0]);
#else
        NULL;
    printf("%s: using just NULL as argv...\n", argv[0]);
#endif
    printf("%s: argv == %p\n", argv[0], ptr);
    ret = execve(argv[1], ptr, envp);

    printf("%s: execve failed ;_; got %s\n", argv[0], strerror(ret));
    return 0;
}