Conversion from LPVOID to HANDLE[] Win32/c++

[RedSon]

Hi all,

HANDLE hnd = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadProc, (LPVOID)handleArray, 0, &dwThread);
 
...
 
DWORD ThreadProc(LPVOID lpParameter)
{    
 
HANDLE hArray[NUM_EVENTS];
hArray = (HANDLE)&lpParameter;
 
...
 

Error is cannot convert from HANDLE to HANDLE[1]. I know it has something to do with the cast that I have there on that second line of the ThreadProc but, for the life of me, I cannot figure out how to get it right.

Thanks in advance!

[Banfa]

/* I am guessing this */
    HANDLE handleArray[NUM_EVENTS];
 
    HANDLE hnd = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadProc, 
/* At this point we have a pointer of type HANDLE * and 
   cast it to LPVOID */
                   (LPVOID)handleArray, 0, &dwThread);
 
...
 
DWORD ThreadProc(LPVOID lpParameter)
{    
 
    HANDLE hArray[NUM_EVENTS];
 
/* 
  1.  hArray is of type HANDLE [NUM_EVENTS], i.e. an array 
      but the cast is to type HANDLE
  2.  lpParameter contins a HANDLE * but you take a pointer(&) to 
      it which will just be a pointer to somewhere random on the 
      stack not a pointer to the original array.  The & is not required.
  3.  Attemping to assign a pointer to an array is illegal
*/
    hArray = (HANDLE)&lpParameter;
 
...
 

2 options

1. In the thread use a HANDLE pointer and then just use it like an array

DWORD ThreadProc(LPVOID lpParameter)
{    
 
    HANDLE *hArray;
    hArray = (HANDLE)lpParameter;
...
}
 

2. In the thread copy the handles from the pointer to the array

DWORD ThreadProc(LPVOID lpParameter)
{    
    HANDLE hArray[NUM_EVENTS];
 
    memcpy((void *)hArray, lpParameter, sizeof hArray);
...
}
 

[RedSon]

You know I think I got confused because in that Thread Proc I am using a method called MsgWaitForMultipleObjects which needs an array of object handles. I'll go with option 1 since it's simple.

Thanks for the help!

[RedSon]

2 options

1. In the thread use a HANDLE pointer and then just use it like an array

DWORD ThreadProc(LPVOID lpParameter)
{    
 
    HANDLE *hArray;
    hArray = (HANDLE)lpParameter;
...
}
 

That is almost right...still a type mismatch

 
DWORD ThreadProc(LPVOID lpParameter)
{    
 
    HANDLE *hArray;
    hArray = (HANDLE*)lpParameter;
...
}
 

No worries, compiler caught it straight away and complained about it. Easy fix too. :D

[Banfa]

So? Even experts like me can still make typing mistakes :D

[RedSon]

Sure, sure... "a typing mistake" LOL :D