Returns the value with its byte order reversed.

This function reverses the byte sequence of the specified 64-bit value. It is a low-level primitive and should not be used directly for generic endianness conversion; specific macros (such as stLEToCPU64) should be used for that purpose to ensure architectural portability.

This function is excluded from compilation if 64-bit integer support is disabled by setting AR_USE_64_BIT to 0, or if the byte ordering module is disabled by setting ST_USE_ENDIANS to 0.