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Re: .*Console.* Functions vs. tty


On Mon, Oct 29, 2001 at 12:29:32PM -0600, Parker, Ron wrote:
> I am working on a program that offers a choice of user interfaces at run
> time, similar to what xemacs does.  This application is designed to be
> portable at least between cygwin, Linux, and native Windows.  One of the
> UI's uses the standard console interfaces.  However, when the code runs
> under cygwin with "tty" enabled, I cannot get the console screen buffer
> information.  This is not dependent upon it being a cygwin compiled
> application.  It "malfunctions" if compiled by gcc for cygwin, gcc for
> MinGW, or MSVC.
> 
> I have narrowed the problem down to a simple portion of code, which will
> exhibit the same behavior as my application.  The GetConsoleScreenBufferInfo
> function fails with error 6, ERROR_INVALID_HANDLE.  
> 
> How can I work around this without forcing the user to use "notty"?
> 
> #include <windows.h>
> 
> int main()
> {
>   int retval = 0;
>   CONSOLE_SCREEN_BUFFER_INFO csbi;
>   
>   HANDLE output = GetStdHandle(STD_OUTPUT_HANDLE);

According to MSDN you need a handle with GENERIC_READ access to
call GetConsoleScreenBufferInfo with. That's not necessarily 
true for an output handle...

Corinna

> 
>   AllocConsole();
>   if (output == INVALID_HANDLE_VALUE)
>   {
>     printf("GetStdHandle failed: %ld\n", GetLastError());
>     retval = 1;
>   }
>   else if (!GetConsoleScreenBufferInfo(output, &csbi))
>   {
>     printf("GetConsoleScreenBufferInfo failed: %ld\n", GetLastError());
>     retval = 2;
>   }
>   else
>     printf("Success.");
> 
>   return retval;
> }
> 
> 
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-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin@cygwin.com
Red Hat, Inc.

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