4 ms·
gotos are sometimes used in C for error handling (to release resources), it's a simple way to do cleanup: void foo() { int* foo = malloc(...)
by lorenzhs 11y ago
gotos are sometimes used in C for error handling (to release resources), it's a simple way to do cleanup:
void foo() {
int* foo = malloc(...)
if (foo == NULL) goto err_foo;
int* bar = malloc(...)
if (bar == NULL) goto err_bar;
/* code */
err_bar:
free(bar);
err_foo:
free(foo);
}
That's a use of goto that's often considered non-evil, probably because the alternatives are typically a lot more ugly.
- lokeshk 11y agoSorry to be a stickler, but the error handling in your method "frees" a resource even when nothing was allocated to it. Freeing a null pointer is as such an undefined behavior.
- Someone 11y agohttp://www.open-std.org/JTC1/SC22/wg14/www/docs/n1124.pdf http://www.open-std.org/JTC1/SC22/wg14/www/docs/n1124.pdf, section 7.20.3.2 "The free function": "The free function causes the space pointed to by ptr to be deallocated, that is, made available for further allocation. If ptr is a null pointer, no action occurs."
- PeCaN 11y agoDereferencing a null pointer is undefined behavior. free() on NULL is defined to be a no-op.