Hi José, Is there any reason you can't use int64_t from <stdint.h>? Or use int64_t indirectly by: #include <stdint.h> typedef int64_t matrix_index; The difficulty then will be to scrub your code to replace your int index types with matrix_index index type. On a 64-bit machine, where the natural word size is 64, I think that int should be 64-bit. But apparently my preferences are not in vogue. On all the 64-bit machines I use, int is half-word size (32-bit). Sincerely, --Eljay
