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qSem.c File Reference

Semaphore Handling API. More…

Functions
int	qSemInit (const char *keyfile, int keyid, int nsems, bool autodestroy)
	Under-development.
int	qSemGetId (const char *keyfile, int keyid)
	Under-development.
bool	qSemEnter (int semid, int semno)
	Under-development.
bool	qSemEnterNowait (int semid, int semno)
	Under-development.
bool	qSemEnterForce (int semid, int semno, int maxwaitms, bool *forceflag)
	Under-development.
bool	qSemLeave (int semid, int semno)
	Under-development.
bool	qSemCheck (int semid, int semno)
	Under-development.
bool	qSemFree (int semid)
	Under-development.

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Detailed Description

Semaphore Handling API.

Note:

   [daemon main]
   #define MAX_SEMAPHORES (2)
 
   // create semaphores
   int semid = qSemInit("/some/file/for/generating/unique/key", 'q', MAX_SEMAPHORES, true);
   if(semid < 0) {
     printf("ERROR: Can't initialize semaphores.n");
     return -1;
   }
   // fork childs
   (... child forking codes ...)
   // at the end of daemon, free semaphores
   if(semid >= 0) qSemFree(semid);
   [forked child]
   // critical section for resource 0
   qSemEnter(0);
   (... guaranteed as atomic procedure ...)
   qSemLeave(0);
   (... some codes ...)
   // critical section for resource 1
   qSemEnter(1);
   (... guaranteed as atomic procedure ...)
   qSemLeave(1);
   [other program which uses resource 1]
   int semid = qSemGetId("/some/file/for/generating/unique/key", 'q');
   if(semid < 0) {
     printf("ERROR: Can't get semaphore id.n");
     return -1;
   }
   // critical section for resource 1
   qSemEnter(1);
   (... guaranteed as atomic procedure ...)
   qSemLeave(1);

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Function Documentation

int qSemInit	(	const char *	keyfile,
		int	keyid,
		int	nsems,
		bool	autodestroy
	)

Under-development.

Since:

not released yet

int qSemGetId	(	const char *	keyfile,
		int	keyid
	)

Under-development.

Since:

not released yet

bool qSemEnter	(	int	semid,
		int	semno
	)

Under-development.

Since:

not released yet

bool qSemEnterNowait	(	int	semid,
		int	semno
	)

Under-development.

Since:

not released yet

bool qSemEnterForce	(	int	semid,
		int	semno,
		int	maxwaitms,
		bool *	forceflag
	)

Under-development.

Since:

not released yet

bool qSemLeave	(	int	semid,
		int	semno
	)

Under-development.

Since:

not released yet

bool qSemCheck	(	int	semid,
		int	semno
	)

Under-development.

Since:

not released yet

bool qSemFree

(

int

semid

)

Under-development.

Since:

not released yet

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