freebsd-src/contrib/mandoc/test-strlcat.c

#include <string.h>

int
main(void)
{
	char buf[3] = "a";
	return ! (strlcat(buf, "b", sizeof(buf)) == 2 &&
	    buf[0] == 'a' && buf[1] == 'b' && buf[2] == '\0');
}