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However, this commonly recommended idiom has problems with zero length allocations. If the value of nsize in this example is 0, the standard allows the option of either returning a null pointer or returning a pointer to an invalid (e.g., zero-length) object. However, the standard does not dictate what the return value should be in either case. In cases where the realloc() function frees the memory but returns a null pointer, execution of this code will result in a double-free when free() is called.
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