<p>To send a serial string character to the serial port.  I would need to call WriteFile(handle, "A", strlen("A"), ...)</p>

<p>However, what if I want to specify and send a hex or binary number?  For example, I want to send WriteFile(handle, 0x41, sizeOf(0x41), ...) ?</p>

<p>Is there a function that allow me to do this?</p>

If you just want to write one byte, it still needs to be in an array.
So you would need:
```
```
int buffer[1024];
buffer[0] = 42;

WriteFile(handle, buffer, 1);
```
```
See this:
http://msdn.microsoft.com/en-us/library/aa365747(VS.85).aspx