InterlockedCompareExchange

Conditional exchange

Declaration

Source position: systemh.inc line 1530

  function InterlockedCompareExchange(var Target: LongInt; 
                                     NewValue: LongInt; 
                                     Comperand: LongInt) : LongInt;
  function InterlockedCompareExchange(var Target: Pointer; 
                                     NewValue: Pointer; 
                                     Comperand: Pointer) : Pointer;
  function InterlockedCompareExchange(var Target: Cardinal; 
                                     NewValue: Cardinal; 
                                     Comperand: Cardinal) : Cardinal;

Description

InterlockedCompareExchange does an compare-and-exchange operation on the specified values in a thread-safe way. The function compares Target and Comperand and exchanges Target with NewValue if Target and Comperand are equal. It returns the old value of Target. This is done in a thread-safe way, i.e., only one processor is accessing the Target variable at a time.

Errors

None.

See also

Name	Description
InterLockedDecrement	Thread-safe decrement
InterLockedExchange	Exchange 2 integers in a thread-safe way
InterLockedExchangeAdd	Thread-safe add and exchange of 2 values
InterLockedIncrement	Thread-safe increment