General Info
Interface: Semaphore Files: lib/semaphore.h Last change: 23/12/2001 Author: Luiz Henrique Shigunov	Description Structures
Functions
0x00 - Destroy - Destroy a semaphore 0x01 - Init - Initialize a semaphore 0x02 - P - Lock a semaphore	0x03 - TryP - Try to lock a semaphore 0x04 - V - Unlock a semaphore

Description

This page describes Semaphore user interface.

Semaphores are usually used to control the use of shared resources.

Structures

typedef struct {
    int count;
    unsigned int data[3];
} Semaphore;

int Destroy(Semaphore *s);

This function destroys semaphore s, freeing its resources.

The semaphore can't be in use.

int Init(Semaphore *s, int value, int prop);

This function initializes semaphore s with count value and properties prop.

prop isn't used yet.

int P(Semaphore *s);

This function locks semaphore s.

If the semaphore count is less or equal to 0, P blocks the calling thread until count becomes positive.

int TryP(Semaphore *s);

This functions tries to lock semaphore s.

It behaves identically to P, but returns an error if the thread would block.

int V(Semaphore *s);

This function unlocks semaphore s.