Is it good practice to free a NULL pointer in C? [duplicate]

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Quoting the C standard, 7.20.3.2/2 from ISO-IEC 9899:

void free(void *ptr);

If ptr is a null pointer, no action occurs.

Don’t check for NULL, it only adds more dummy code to read and is thus a bad practice.

However, you must always check for NULL pointers when using malloc & co. In that case NULL mean that something went wrong, most likely that no memory was available.

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