Mega Code Archive
Setting comm port configuration programmatically under win95
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Question:
How can I set the comm ports configuration programmatically
under Windows 95?
Answer:
The following example demonstrates setting the comm port under
Windows95.
Example:
procedure TForm1.Button1Click(Sender: TObject);
var
CommPort : string;
hCommFile : THandle;
Buffer : PCommConfig;
size : DWORD;
begin
CommPort := 'COM1';
{Open the comm port}
hCommFile := CreateFile(PChar(CommPort),
GENERIC_WRITE,
0,
nil,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
0);
if hCommFile=INVALID_HANDLE_VALUE then
begin
ShowMessage('Unable to open '+ CommPort);
exit;
end;
{Allocate a temporary buffer}
GetMem(Buffer, sizeof(TCommConfig));
{Get the size of the CommConfig structure}
{as it may be different than documented}
size := 0;
GetCommConfig(hCommFile, Buffer^, size);
{Free the temporary buffer}
FreeMem(Buffer, sizeof(TCommConfig));
{Allocate the CommConfig structure}
GetMem(Buffer, size);
GetCommConfig(hCommFile, Buffer^, size);
{Change the baud rate}
Buffer^.dcb.BaudRate := 1200;
{Set the comm port to the new configuration}
SetCommConfig(hCommFile, Buffer^, size);
{Free the buffer}
FreeMem(Buffer, size);
{Close the comm port}
CloseHandle(hCommFile);
end;
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