#include <semaphore.h>

Public Member Functions

semaControl ()
semaControl (const char *dir)
int number ()
int value (int nr)
void markForDelete ()
void open ()
void create (int members)
void lock (int nr)
void unlock (int nr)
key_t getKey ()

Private Member Functions

void init (const char *dir)

Private Attributes

int sid
int memid
int max
key_t key

Detailed Description

The class semaControl is intended to maintain the state of the semaphore arrays.

Every instance contains the key information of the array. (Calculated form a directory name and the project character 's' for semaphore, see SysV key!). The instance not necessarily contains a valid semaphore identifier (sid) - before any other command use open() or create().

To supervise the semaphores form system level use the OS commands ipcs, ipcrm.

Todo:: How can I get a list of all known semaphores?

Definition at line 158 of file semaphore.h.

Constructor & Destructor Documentation

semaControl::semaControl ( )

semaControl::semaControl ( const char * dir )

Creates a Semaphore array.

Parameters:

dir	Name of the base directory

Member Function Documentation

void semaControl::create ( int members )

Create a new array of semaphores.

key_t semaControl::getKey ( )

Returns the key of the semphore array This is the number that can be found in the display of the system command "ipcs".

void semaControl::init ( const char * dir ) [private]

void semaControl::lock ( int nr )

Lock a semphore.

WARNING: The method will modify a semaphore independantly of the access rights

void semaControl::markForDelete ( )

Mark the semaphore for delete.

Do not use this command on a semaphore array another process may depend on.

int semaControl::number ( )

Returns the number of semaphores in the array.

void semaControl::open ( )

Open semaphore pointer to an existing semaphore.

void semaControl::unlock ( int nr )

Unlock a semphore.

WARNING: The method will modify a semaphore independantly of the access rights

int semaControl::value ( int nr )

Returns the value of a semaphore.

Have always in mind, that in a running system it is useless to read the value of a semaphore. The information is only valid for the time the value is read. You can base any decicions on tis value! Use request() instead.

Member Data Documentation

key_t semaControl::key [private]

Definition at line 221 of file semaphore.h.

int semaControl::max [private]

Definition at line 219 of file semaphore.h.

int semaControl::memid [private]

Definition at line 218 of file semaphore.h.

int semaControl::sid [private]

Definition at line 217 of file semaphore.h.

The documentation for this class was generated from the following file:

/home/kopmann/git-mirror/fdhwlib/fdhwlib/akutil/semaphore.h