QHelp previews:

Guarded Free

The free function, which deallocates heap memory, may accept a NULL pointer and take no action. Therefore, it is unnecessary to check its argument for the value of NULL before a function call to free. As such, these guards may hinder performance and readability.

Recommendation

A function call to free should not depend upon the value of its argument. Delete the if condition preceeding a function call to free when its only purpose is to check the value of the pointer to be freed.

Example

void test()
{
    char *foo = malloc(100);
    // BAD
    if (foo)
        free(foo);
    // GOOD
    free(foo);
}

References

• The Open Group Base Specifications Issue 7, 2018 Edition: free - free allocated memory