tom peng wrote: > Are those 32-bit / 64-bit difference stipulated in C/C++ standard or ruled > by the GNU/GCC compiler? All the standard says is that sizeof(short) <= sizeof(int) <= sizeof(long), it doesn't give any actual numbers, other than sizeof(char) = 1. The choice of what the particular values are is defined by the platform's ABI specification, not gcc. gcc just follows the spec for each platform. It's very broken to assume that sizeof(long) is 4, because that is not true on almost any 64 bit platform, the major exception begin Windows x64. It's especially broken considering that the C99 standard gives you the header <stdint.h>, which provides int32_t, uint32_t, int64_t, uint64_t, and so on. Brian
