ioctl-test.c

#include <linux/ioctl.h>
#include <stdio.h>

int main(int argc, char **argv) {
	printf("_IO('q', 10)  => 0x%08lX\n", (unsigned long int)_IO('q', 10));
	printf("_IO('a', 255) => 0x%08lX\n", (unsigned long int)_IO('a', 255));

	printf("_IOW('z', 10, char[1]) => 0x%04lX\n", _IOW('z', 10, char[1]));
	printf("_IOW('z', 10, char[512] => 0x%04lX\n", _IOW('z', 10, char[512]));
	printf("_IOW('z', 10, char[1 << 32] => 0x%04lX\n", _IOW('z', 10, char[1 << 32])); // _IOC_SZ_BITS = 14
	
	printf("_IOR('z', 10, char[1]) => 0x%04lX\n", _IOR('z', 10, char[1]));
	printf("_IOR('z', 10, char[512]) => 0x%04lX\n", _IOR('z', 10, char[512]));
	printf("_IOR('z', 10, char[1 << 32] => 0x%04lX\n", _IOR('z', 10, char[1 << 32])); // _IOC_SZ_BITS = 14

	printf("_IOWR('z', 10, char[1]) => 0x%04lX\n", _IOWR('z', 10, char[1]));
	printf("_IOWR('z', 10, char[512]) => 0x%04lX\n", _IOWR('z', 10, char[512]));
	printf("_IOWR('z', 10, char[1 << 32] => 0x%04lX\n", _IOWR('z', 10, char[1 << 32])); // _IOC_SZ_BITS = 14
}

output.txt

_IO('q', 10)  => 0x0000710A
_IO('a', 255) => 0x000061FF
_IOW('z', 10, char[1]) => 0x40017A0A
_IOW('z', 10, char[512] => 0x42007A0A
_IOW('z', 10, char[1 << 32] => 0x40007A0A
_IOR('z', 10, char[1]) => 0x80017A0A
_IOR('z', 10, char[512]) => 0x82007A0A
_IOR('z', 10, char[1 << 32] => 0x80007A0A
_IOWR('z', 10, char[1]) => 0xC0017A0A
_IOWR('z', 10, char[512]) => 0xC2007A0A
_IOWR('z', 10, char[1 << 32] => 0xC0007A0A