Re: [bug-gawk] in-place edit request

[Andrew J. Schorr]

Perhaps this recipe may work:
http://stackoverflow.com/questions/4832603/how-could-i-temporary-redirect-stdout-to-a-file-in-a-c-program

It is also discussed here:
http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/redirecting-standard-io.html

Here's a test harness for that approach.  It seems to work on Linux
and on Cygwin:

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

int
main(int argc, char **argv)
{
   int bak, new;
   char instr[1024];

   puts("output on regular stdout");

   /* switch stdout to argument file */
   fflush(stdout);
   bak = dup(1);
   new = open(argv[1], O_WRONLY|O_CREAT, 0666);
   dup2(new, 1);
   close(new);

   while (fgets(instr, sizeof(instr), stdin))
      fputs(instr, stdout);

   /* restore stdout */
   fflush(stdout);
   dup2(bak, 1);
   close(bak);

   puts("after returning to regular stdout");
   return 0;
}

This obviously needs more error checking, but it seems to work.
So perhaps this can be packaged into an extension function after all.
Is this approach likely to work on all supported platforms?

Regards,
Andy