+ char * prefix = "Trouble with malloc() in ";
+ char * msg = malloc(strlen(prefix) + strlen(f) + 1 + 1);
+ exit_err(NULL == msg,
+ "Trouble in try_malloc() with malloc() for error message string.");
+ int test = sprintf(msg, "%s%s.", prefix, f);
+ exit_err(test < 0, "Trouble in try_malloc() with sprintf().");