This article was previously published under Q115831
CreateFile() can be used to get a handle to a serial port. The "Win32Programmer's Reference" entry for "CreateFile()" mentions that the sharemode must be 0, the create parameter must be OPEN_EXISTING, and thetemplate must be NULL.
CreateFile() is successful when you use "COM1" through "COM9" for the nameof the file; however, the message
is returned if youuse "COM10" or greater.
If the name of the port is \\.\COM10, the correct way to specify the serialport in a call to CreateFile() is as follows:
CreateFile( "\\\\.\\COM10", // address of name of the communications device fdwAccess, // access (read-write) mode 0, // share mode NULL, // address of security descriptor OPEN_EXISTING, // how to create 0, // file attributes NULL // handle of file with attributes to copy );
NOTES: This syntax also works for ports COM1 through COM9. Certain boardswill let you choose the port names yourself. This syntax works for thosenames as well.