Return to README CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / php / ext / shmop

5.4.17

    1: last update Jan 2, 2002 (hackie@prohost.org/ilia@prohost.org)
    2: 
    3: Shared Memory Operations Extension to PHP
    4: 
    5: 	While developing a search deamon we needed a php based front end
    6: 	to communicate the deamon via SHM. PHP already had a shared memory
    7: 	extension (sysvshm) written by Christian Cartus <cartus@atrior.de>,
    8: 	unfortunately this extension was designed with PHP only in mind and
    9: 	offers high level features which are extremly bothersome for basic SHM
   10: 	we had in mind.  After spending a day trying to reverse engineer and figure
   11: 	out the format of sysvshm we decided that it would be much easier to
   12: 	add our own extension to php for simple SHM operations, we were right :)). 
   13: 
   14: the functions are:
   15: 	
   16: int shmop_open(int key, string flags, int mode, int size)
   17: 	
   18: 	key 		- the key of/for the shared memory block
   19: 	flags 		- 4 flags are avalible 
   20: 				a for read only access (sets SHM_RDONLY)
   21: 				w for read & write access
   22: 				c create or open an existing segment (sets IPC_CREATE)
   23: 				n create a new segment and fail if one already exists under same name (sets IPC_CREATE|IPC_EXCL)
   24: 				(the n flag is mostly useful for security perpouses, so that you don't end up opening a faked segment 
   25: 				if someone guesses your key)
   26: 	mode		- acsess mode same as for a file (0644) for example
   27: 	size		- size of the block in bytes
   28: 	
   29: 	returns an indentifier
   30: 	
   31: 
   32: char shmop_read(int shmid, int start, int count)
   33: 
   34: 	shmid		- shmid from which to read
   35: 	start		- offset from which to start reading
   36: 	count		- how many bytes to read
   37: 	
   38: 	returns the data read
   39: 
   40: int shmop_write(int shmid, string data, int offset)
   41: 
   42: 	shmid		- shmid from which to read
   43: 	data		- string to put into shared memory
   44: 	offset		- offset in shm to write from
   45: 	
   46: 	returns bytes written
   47: 	
   48: int shmop_size(int shmid)
   49: 
   50: 	shmid 		- shmid for which to return the size
   51: 	
   52: 	returns the size in bytes of the shm segment
   53: 	
   54: 	
   55: int shmop_delete(int shmid)
   56: 
   57: 	marks the segment for deletion, the segment will be deleted when all processes mapping it will detach
   58: 
   59: 	shmid		- shmid which to mark for deletion
   60: 	
   61: 	returns 1 if all ok, zero on failure
   62: 	
   63: int shmop_close(int shmid)
   64: 
   65: 	shmid 		- shmid which to close
   66: 	
   67: 	returns zero
   68: 	
   69: