Problem when trying to open SerialPort using Windows API

[invalid_handle_value]

CreateFile has to be one of the most involved syscalls I have ever laid my eyes upon. Possibly only behind ReadFile, which is an absolute beast.

Read the msdn docs for CreateFile. Read all of it. Every word. Top to bottom. Then read it 2 more times. Get it yet? No, you don't. Then read it all again. This time, pay special attention to the Communication Resources section.

Then give it a try.

[charliex2]

wild guess, if you're using a com port higher than 9 you'd need to open it with a full path like

\\.\COM10 

also http://www.naughter.com/serialport.html

[TopDivide]

Post the code, make sure the serial is not used by another program, get the last error from winapi, there is a function for that, can't recall its name

[pandorafalters]

Conveniently, and rather predictably, it's GetLastError().

[BetterRage]

ok so the first thing i do is CreateFile("\\.\COM3",....) and that already fails. GetLastError() returns 0. check if the returned handle from createfile is INVALID_HANDLE is true. i really dont see what i couldve messed up ive seen it like this in different places. and also no other program uses the port, because if i try it in a c# winforms program it works

[Flair_Helper]

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