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Date: Sun, 13 Nov 2005 17:09:03 +0100
From: Christian Franke <Christian DOT Franke AT t-online DOT de>
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To: cygwin AT cygwin DOT com
Subject: setsid() does not call FreeConsole() even if all files are closed
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Hi,

when starting a daemon from the console, the console will not close 
before the daemon finishes.

Try, e.g:

$ /usr/sbin/syslogd
$ exit

Shell exits, but console window persists until syslogd is terminated.

Workaround:

   setsid();
+  #ifdef __CYGWIN__
+  FreeConsole();
+  #endif


The attached program demonstrates the issue.

If run without an argument, the output line is written to current console.
It should be written to a new console, but AllocConsole() does nothing 
because the current console is still attached.

If run with any argument, FreeConsole is called after setsid().
It should return FALSE, but returns TRUE (status=1).
Then the output line is written to a new console.

According to syscall.cc:setsid(), FreeConsole() should be called if a 
tty exists and no files are open.

Diagnostic via strace doesn't help. The program works as expected if run 
via strace ... interesting?-)

Thanks for any help

Christian


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#include <stdio.h>
#include <unistd.h>
#include <windows.h>

main(int argc, char **argv)
{
  if (fork())
    return 0;

  fclose(stdin); fclose(stdout); fclose(stderr);

  setsid();

  int status = -1;
  if (argc > 1)
    status = FreeConsole();

  sleep(10);

  AllocConsole();
  freopen("/dev/conout", "w", stdout);
  printf("Welcome back, status=%d\n", status);
  sleep(20);

  return 0;
}


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