Opening temporary files for std.process.spawnProcess input/output

[wobbles via Digitalmars-d-learn]

On Wednesday, 25 February 2015 at 19:09:16 UTC, Ali Çehreli wrote:
> On 02/25/2015 05:56 AM, wobbles wrote:
>
> > Hi,
> > Any reason why the following wont work?
> >
> > void main(string[] args)
> > {
> >      auto pidIn = File.tmpfile();
> >      auto pidOut = File.tmpfile();
> >      auto pid = spawnProcess(["ls", "./"], pidIn, pidOut,
> > std.stdio.stdout, null, Config.newEnv);
> >
> >      if(wait(pid) == 0)
> >          writefln("%s", pidOut.readln());
> > }
> >
> > The pidOut.readln() throws this exception:
> > object.Exception@/usr/include/dmd/phobos/std/stdio.d(1377):
> Attempt to
> > read from an unopened file.
> >
> > I figured tmpfile() would be open for read/write by default?
> > Also, theres no way to pass in args to File.tmpfile() to make
> them
> > read/write.
> >
> > Any ideas?
>
> It looks like the file is closed when spawnProcess is finished. 
> I don't know whether it is done by spawnProcess explicitly or 
> whether it is a behavior for temporary files.
>
> How about using a pipe? The following works:
>
> import std.stdio;
> import std.process;
>
> void main(string[] args)
> {
>     auto pidIn = File.tmpfile();
>     auto pidOut = pipe();
>     auto pid = spawnProcess(["ls", "./" ],
>                             pidIn, pidOut.writeEnd,
>                             std.stdio.stdout, null, 
> Config.newEnv);
>
>     if(wait(pid) == 0)
>         writeln(pidOut.readEnd.byLine);
> }
>
> Ali

This works, Thanks folks!