Call this member function to gain access to the critical section object.
BOOL Lock( );
BOOL Lock(
DWORD dwTimeout
);
Parameters
- dwTimeout
Lock ignores this parameter value.
Return Value
Nonzero if the function was successful; otherwise 0.
Remarks
Lock is a blocking call that will not return until the critical section object is signaled (becomes available).
If timed waits are necessary, you can use a CMutex object instead of a CCriticalSection object.
If Lock fails to allocate the necessary system memory, a memory exception (of type CMemoryException) is automatically thrown.
Example
This example demonstrates the nested critical section approach by controlling access to a shared resource (the static _strShared object) using a shared CCriticalSection object. The SomeMethod function demonstrates updating a shared resource in a safe manner.
//Definition of critical section class
class CMyCritSectClass
{
static CString _strShared; //shared resource
static CCriticalSection _critSect;
public:
CMyCritSectClass(void) {}
~CMyCritSectClass(void) {}
void SomeMethod(void); //locks, modifies, and unlocks shared resource
};
//Declaration of static members and SomeMethod
CString CMyCritSectClass::_strShared;
CCriticalSection CMyCritSectClass::_critSect;
void CMyCritSectClass::SomeMethod()
{
_critSect.Lock();
if (_strShared == "")
_strShared = "<text>";
_critSect.Unlock();
}
Requirements
Header: afxmt.h