A short example to in C to clear an enviroment variable using the libc function unsetenv

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

int main(int argc, char **argv) {

	if (unsetenv("HOME") < 0) {
		perror("unsetenv");
		exit(EXIT_FAILURE);
	}

	system("env | grep HOME");
	return 0;
}