Always check malloc'ed memory?

Question

I often catch myself doing the following (in non-critical components):

some_small_struct *ptr=(some_small_struct *) malloc(sizeof(some_small_struct));
ptr-&g         


        

Answer 1

Assuming that you are running on a Linux/MaxOs/Windows or other virtual memory system, then... the only reason to check the return value from malloc is if you have a strategy for freeing up enough memory to allow the program to continue running. An informative message will help in diagnosing the problem, but only if your program caused the out-of-memory situation. Usually it is not your program and the only thing that your program can to do help is to exit as quickly as possible.

assert(ptr != NULL);

will do all of these things. My usual strategy is to have a layer around malloc that has this in it.

void *my_malloc(size_t size)
{
    void *ptr = malloc ( size );
    assert(ptr != NULL);
    return *ptr;
}

Then you call my_malloc instead of malloc. During development I use a memory allocation library that is conducive to debugging. After that if it runs out of memory - I get a message.