pfunc/futex.h File Reference

#include <sys/syscall.h>
#include <unistd.h>
#include <errno.h>
#include <pfunc/environ.hpp>

Go to the source code of this file.

Defines
#define	SYS_futex   202
#define	FUTEX_WAIT   0
#define	FUTEX_WAKE   1
Functions
static PFUNC_INLINE void	futex_wait (int *addr, int val)
	Atomically checks if the value at the given address is what is expected. If so, the the calling thread is put to sleep waiting on a futex_wake call to occur. If the value at the address has changed, the calling thread returns without entering the kernel.
static PFUNC_INLINE void	futex_wake (int *addr, int nthreads)
	Wakes up the specified number of threads which are sleeping on using futex_wait at the given address.
static PFUNC_INLINE void	cpu_relax (void)
	Performs a nop -- basically a way to ensure we are not using memory.

---

Define Documentation

#define FUTEX_WAIT   0

#define FUTEX_WAKE   1

#define SYS_futex   202

---

Function Documentation

static PFUNC_INLINE void cpu_relax

(

void

)

[static]

Performs a nop -- basically a way to ensure we are not using memory.

static PFUNC_INLINE void futex_wait	(	int *	addr,
		int	val
	)		[static]

Atomically checks if the value at the given address is what is expected. If so, the the calling thread is put to sleep waiting on a futex_wake call to occur. If the value at the address has changed, the calling thread returns without entering the kernel.

Parameters:

[in]	addr	Address at which the value needs to be checked.
[in]	val	The value if found at the given address, the sleep should be entering.

static PFUNC_INLINE void futex_wake	(	int *	addr,
		int	nthreads
	)		[static]

Wakes up the specified number of threads which are sleeping on using futex_wait at the given address.

Parameters:

[in]	addr	Address at which the threads are waiting.
[in]	nthreads	The number of threads to wake up.