writing to stdout in an windows app without a console
Duncan Coutts
duncan.coutts at worc.ox.ac.uk
Wed Feb 16 09:05:47 EST 2005
On Wed, 2005-02-16 at 14:31 +0200, Krasimir Angelov wrote:
> On Wed, 16 Feb 2005 12:01:06 +0000, Duncan Coutts
> <duncan.coutts at worc.ox.ac.uk> wrote:
> > What's your opinion of making writing to stdout fail without raising an
> > exception when the application is compiled with --subsystem
> > windows?
>
> I think the current behaviour is the right one. After all we don't
> have valid stdout/stdin and I don't see any reason to hide this.
True, but it's not the behaviour that other windows programming systems
implement:
For example MS's C library happily ignores output to stdout:
#include <stdio.h>
int main () {
int res_code = fprintf(stdout, "hello world!\n");
fprintf(stderr, "res_code = %d\n", res_code);
return 0;
}
now compiling with mingw's gcc:
gcc testio.c -Xlinker --subsystem -Xlinker windows
and from a windows console (ie not a msys / cygwin window)
a.exe 2> err
then saying "type err" gives us the output:
res_code = 13
which is the number of characters output. Upon an error it would have
been negative (according to the fprintf man page).
As I said before I don't know which part of the windows stack implements
this behaviour (papering over the fact there is no stdout handle) but it
is apparently standard behaviour.
Duncan
More information about the Glasgow-haskell-users
mailing list