Answer by mav_2k for maximum memory which malloc can allocate

As per C90 standard guarantees that you can get at least one object 32 kBytes in size, and this may be static, dynamic, or automatic memory. C99 guarantees at least 64 kBytes. For any higher limit, refer your compiler's documentation.

Also, malloc's argument is a size_t and the range of that type is [0,SIZE_MAX], so the maximum you can request is SIZE_MAX, which value varies upon implementation and is defined in <limits.h>.