A common idiom that is no longer as common is to always create a stack buffer up to a certain small bound and then an allocation if it goes beyond: void dwi

A common idiom that is no longer as common is to always create a stack buffer up to a certain small bound and then an allocation if it goes beyond: void dwim(unsigned count) { struct Something _buffer[10]; struct Something* buffer; if (count < sizeof(_buffer) / sizeof(_buffer[0])) buffer = _buffer; else { buffer = (struct Something*) malloc(count * sizeof(struct Something)); } doSomething(buffer, count); if (buffer != _buffer) free(buffer); } It used to be really common to write that without considering if it was a necessary optimization or not - nowadays I would just malloc up front.