futex.h

#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H

/* Second argument to futex syscall */


#define FUTEX_WAIT		0
#define FUTEX_WAKE		1
#define FUTEX_FD		2
#define FUTEX_REQUEUE		3
#define FUTEX_CMP_REQUEUE	4
#define FUTEX_WAKE_OP		5

long do_futex(unsigned long uaddr, int op, int val,
		unsigned long timeout, unsigned long uaddr2, int val2,
		int val3);

#define FUTEX_OP_SET		0	/* *(int *)UADDR2 = OPARG; */
#define FUTEX_OP_ADD		1	/* *(int *)UADDR2 += OPARG; */
#define FUTEX_OP_OR		2	/* *(int *)UADDR2 |= OPARG; */
#define FUTEX_OP_ANDN		3	/* *(int *)UADDR2 &= ~OPARG; */
#define FUTEX_OP_XOR		4	/* *(int *)UADDR2 ^= OPARG; */

#define FUTEX_OP_OPARG_SHIFT	8	/* Use (1 << OPARG) instead of OPARG.  */

#define FUTEX_OP_CMP_EQ		0	/* if (oldval == CMPARG) wake */
#define FUTEX_OP_CMP_NE		1	/* if (oldval != CMPARG) wake */
#define FUTEX_OP_CMP_LT		2	/* if (oldval < CMPARG) wake */
#define FUTEX_OP_CMP_LE		3	/* if (oldval <= CMPARG) wake */
#define FUTEX_OP_CMP_GT		4	/* if (oldval > CMPARG) wake */
#define FUTEX_OP_CMP_GE		5	/* if (oldval >= CMPARG) wake */

/* FUTEX_WAKE_OP will perform atomically
   int oldval = *(int *)UADDR2;
   *(int *)UADDR2 = oldval OP OPARG;
   if (oldval CMP CMPARG)
     wake UADDR2;  */

#define FUTEX_OP(op, oparg, cmp, cmparg) \
  (((op & 0xf) << 28) | ((cmp & 0xf) << 24)		\
   | ((oparg & 0xfff) << 12) | (cmparg & 0xfff))

#endif