Variable used without being initialized?

Why would this code be throwing the "run-time check failure #3 - the variable 'SQLStrtTime' variable is being used without being initialized" error?

===============================================================
UINT SQL_Thread(LPVOID param)
{
LARGE_INTEGER SQLFreq;
LARGE_INTEGER SQLStrtTime;
LARGE_INTEGER SQLCurrTime;
double SQLDiff;
bool SQLInitTimer1;



for( ;; )
{

// Read/Write SQL Data From/To Database (every 500ms)
if (SQLInitTimer1 = false)
{
QueryPerformanceCounter(&SQLStrtTime);
SQLInitTimer1 = true;
}
else if (SQLInitTimer1 = true)
{
QueryPerformanceCounter(&SQLCurrTime);
QueryPerformanceFrequency(&SQLFreq);
SQLDiff = ((double)(SQLCurrTime.QuadPart - SQLStrtTime.QuadPart) / (double)(SQLFreq.QuadPart)) * 1000;
if (SQLDiff >= 500)
{
UpdateSQL();
SQLInitTimer1 = false;
}
}
}

return 0;

}

================================================================

A couple of things I notice about your code...

First, in your if

Code:

---

if (SQLInitTimer1 = false)
{
        QueryPerformanceCounter(&SQLStrtTime);
        SQLInitTimer1 = true;
}

---

you really need

Code:

---

if (SQLInitTimer1 == false)

---

and instead of

Code:

---

else if (SQLInitTimer1 = true)

---

you need

Code:

---

else if (SQLInitTimer1 == true)

---

Secondly, in this block

Code:

---

if (SQLInitTimer1 == false)
{
        QueryPerformanceCounter(&SQLStrtTime);
        SQLInitTimer1 = true;
}
else if (SQLInitTimer1 == true)
{
        QueryPerformanceCounter(&SQLCurrTime);
        QueryPerformanceFrequency(&SQLFreq);
        SQLDiff = ((double)(SQLCurrTime.QuadPart - SQLStrtTime.QuadPart) / (double)(SQLFreq.QuadPart)) * 1000;
        if (SQLDiff >= 500)
        {
                UpdateSQL();
                SQLInitTimer1 = false;
        }
}

---

If the initial state of SQLInitTime1 is not false, you will fall directly into your else if and SQLStartTime has not yet been initialized.

Hope that helps.

PS - Indentation and the use of code tags would really help you see the flow.

Great, that worked! I'm new at this, thank you for the walk-through!