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Comments on Which platforms return a non-null pointer on malloc(0)

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Which platforms return a non-null pointer on malloc(0)

+4
−2

What is the portability of malloc(0);?

  • Which platforms return NULL without setting errno?
  • Which platforms return a non-null pointer?
  • Do any platforms have some other behavior?
c malloc
posted about 2 months ago
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alx‭
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1 comment thread

realloc(ptr, 0) (1 comment)
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+0
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The behavior of malloc(0) is implementation-defined and varies between platforms. Some platforms will return a NULL pointer, others might return a non-null pointer, but such a pointer should not be used. There's no widely known behavior outside of these.

posted about 1 month ago
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harmony‭
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2 comment threads

errno (1 comment)
re: "but such pointer should not be used" (2 comments)
errno
alx‭ wrote about 1 month ago
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Those are the two return values, but then errno can be 0 or ENOMEM. I think there are various weird combinations of return value and errno in the wild.