Re: STDOUT_FILENO and STDERR_FILENO

[Erik van Pienbroek <erik vanpienbroek nl>]

John Emmas schreef op ma 20-05-2013 om 14:06 [+0100]:
> Also (in 
> theory) it should only attempt to write to the console if stdout / 
> stderr appears to be valid (hopefully Windows would set them to NULL if 
> they weren't valid?).

The documentation about the Win32 API function fileno() has this to say
about that specific situation:

  In Visual C++ 2005, there is a behavior change. If stdout or
  stderr is not associated with an output stream (for example, in
  a Windows application without a console window), the file
  descriptor returned is -2. In previous versions, the file
  descriptor returned was -1. This change allows applications
  to distinguish this condition from an error.

http://msdn.microsoft.com/en-us/library/zs6wbdhx%28v=vs.80%29.aspx

So when there is no valid stdout/stderr the fileno call will return
either -1 or -2. When this value is passed as argument to a write call,
then the write call itself will fail with an 'invalid file descriptor',
but other than that there's shouldn't be any major issues with it.