Starting a thread in a Windows CE 6.0 service - multithreading

Question

I am developing a Windows Service under Windows CE 6.0. The project produces a DLL, which gets integrated in OS Image. The service gets started, when the WinCE boots thanks to registry settings.
The problem is that I am not able to start the "Thread1" thread. I should see the MessageBox, but there is nothing on the screen. Why? Putting the MessageBox into SFC_Init works fine.
Another thing - when I type "services list" in the console (in the WinCE system), the state of my service is unknown... Why is that so?
Please help!
// SrvForCom.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
HINSTANCE hInst;
// main entry point of the DLL
BOOL WINAPI DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
hInst = (HINSTANCE)hModule;
switch(ul_reason_for_call) {
case DLL_PROCESS_ATTACH:
DisableThreadLibraryCalls((HMODULE)hModule);
break;
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
// function called during initialization process
DWORD SFC_Init(DWORD dwContext) {
PSRVCONTEXT pSrv;
HANDLE hThrd;
DWORD err = ERROR_INVALID_PARAMETER;
// fill the info structure
pSrv->servState = SERVICE_STATE_UNKNOWN;
switch (dwContext) {
case SERVICE_INIT_STARTED:
pSrv->servState = SERVICE_STATE_ON;
break;
case SERVICE_INIT_STOPPED:
pSrv->servState = SERVICE_STATE_OFF;
break;
}
// start new thread
hThrd = CreateThread (NULL, 0, Thread1, NULL, 0, NULL);
if (hThrd) {
CloseHandle (hThrd);
err = 0;
} else {
err = GetLastError();
}
return hThrd;
}
BOOL SFC_Deinit(DWORD dwData) {
return TRUE;
}
BOOL SFC_Open(DWORD dwData, DWORD dwAccess, DWORD dwShareMode) {
PSRVCONTEXT pSrv = (PSRVCONTEXT)dwData;
return (DWORD)pSrv;
}
BOOL SFC_Close(DWORD dwData) {
return 1;
}
BOOL SFC_IOControl(DWORD dwData, DWORD dwCode, PBYTE pBufIn,
DWORD dwLenIn, PBYTE pBufOut, DWORD dwLenOut,
PDWORD pdwActualOut) {
PSRVCONTEXT pSrv = (PSRVCONTEXT)dwData;
switch (dwCode) {
case IOCTL_SERVICE_STATUS:
*pBufOut = pSrv->servState;
break;
}
return 1;
}
DWORD WINAPI Thread1(LPVOID lpv) {
MessageBox (NULL, TEXT ("The thread has been successfully started!"), TEXT ("Info"), MB_OK);
return 0;
}

Answer 1

I have found answer to this question. The code above is correct apart from one detail - uninitialized structure. "pSrv" is a pointer (type PSRVCONTEXT) to a struct SRVCONTEXT with "servState" field. When executing "pSrv->servState = SERVICE_STATE_UNKNOWN;" some part of the memmory was overwritten, causing errors in the application.
The solution is to first allocate the memmory to this structure before using it:
pSrv = (PSRVCONTEXT)LocalAlloc (LPTR, sizeof (SRVCONTEXT));
After adding above line to my application, everything started working fine. The thread properly started and the service's state changed to "Running".
P.S. The structure looks like this:
typedef struct {
DWORD servState;
} SRVCONTEXT, *PSRVCONTEXT;