Attempt to represent the S^2->S^3 header reorganisation as a series of "hg rename" operations
2 * Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).
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9 * Initial Contributors:
10 * Nokia Corporation - initial contribution.
17 * Interface : POSIX, semaphores
18 * POSIX implementation of semaphores on Symbian
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46 #ifndef __SEMAPHORE_H__
47 #define __SEMAPHORE_H__
49 #include <sys/types.h>
54 #endif /* __cplusplus */
56 /*Semaphores supported */
59 typedef struct _sem_t* sem_t;
62 This function initializes the semaphore object.
63 The semaphore count is set to the initial count value.
65 IMPORT_C extern int sem_init (sem_t * sem, int pshared, unsigned int value);
68 This function destroys the semaphore object.
70 IMPORT_C extern int sem_destroy (sem_t* sem);
73 This function atomically decrements sem's count if it is greater than 0 and returns immediately,
74 or it returns immediately with a return code of -1 after having set errno to EAGAIN.
75 sem_trywait never blocks.
77 IMPORT_C extern int sem_trywait (sem_t* sem);
80 This function atomically decrements sem's count if it is greater than 0 and returns immediately
81 or it suspends the calling thread until it can resume following a call to sem_post or sem_post_multiple
83 IMPORT_C extern int sem_wait (sem_t* sem);
86 This function atomically decrements sem's count if it is greater than 0 and returns immediately, or it
87 suspends the calling thread. If timeout time lapses before the thread can be resumed because of a sem_post,
88 case, then sem_timedwait returns with a return code of -1 after having set errno to ETIMEDOUT. If the
89 thread can return without suspending then abstime parameter is not checked.
91 IMPORT_C extern int sem_timedwait (sem_t* sem, const struct timespec* abstime);
94 The function increments (unlocks) the semaphore pointed to by sem .
95 If there are threads blocked on the semaphore when sem_post is called, the highest priority thread that has been blocked the longest on
96 the semaphore will be allowed to return from sem_wait .
97 If successful, the function returns zero; otherwise, it returns -1 and set errno to indicate the error.
99 IMPORT_C extern int sem_post (sem_t* sem);
102 This function establish a connection between a named semaphore and a process
104 /* IMPORT_C extern sem_t* sem_open (const char* name,int oflag,mode_t mode, unsigned int value); */
107 This function indicate that the calling process is finished using the named semaphore indicated by sem*/
108 /* IMPORT_C extern int sem_close (sem_t* sem); */
111 This function cleans up resources associated with a system-wide semaphore.
113 /* IMPORT_C extern int sem_unlink (const char* name); */
116 This function updates the location referenced by the sval argument with the value of the semaphore
117 referenced by sem without affecting the state of the semaphore.
118 The updated value represents an actual semaphore value that occurred at some unspecified time
119 during the call, but it need not be the actual value of the semaphore when it is returned to
120 the calling process. If sem is locked, then the object to which sval points shall either be set
121 to zero or to a negative number whose absolute value represents the number of processes waiting
122 for the semaphore at some unspecified time during the call.
124 IMPORT_C extern int sem_getvalue (sem_t* sem, int* sval);
128 } /* End of extern "C" */
129 #endif /* __cplusplus */
131 #endif /* __SEMAPHORE_H__ */