Function _momLock() | Xbase++

Fixes a memory object for access and returns the pointer to the data.

BYTE *_momLock(MomHandle mhObj);

MomHandle mhObj

Handle of a memory object created with _momAlloc(), whose memory area is to be accessed.

Pointer to the first byte of the memory object.

_momLock() is used to access the data of a memory object. As long as a memory object is not locked, its position in memory can be changed by _momResize() or at any time by internal memory packing. The call to _momLock() prevents moving of the object. The data of the memory object can be read and changed via the returned pointer.

_momLock() also coordinates access of several threads to a memory object. If an object is locked from a different thread, _momLock()waits until _momUnlock() is called and then locks the object for this individual thread.

/* 
Generate a memory object and initialize with NULLs. 
*/ 
#include "xppcon.h" 

MomHandle  hNew; 
BYTE      *pNew; 
LONG       size = 50; 

hNew = _momAlloc(size); 
if (hNew != MOM_NULLHANDLE) 
{ 
pNew = _momLock(hNew); 

while (size-- > 0) 
       *pNew++ = 0; 

/* Note: after the following call the value of pNew is invalid */ 
_momUnlock(hNew); 
} 
else 
{ 
/* ... error handling */ 
}

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Function _momLock() Foundation