Running external program from a D program [D2]

[Jonathan M Davis]

Jesse Phillips wrote:
> As you may have noticed by the comments to on bug 3158. exec()[1] calls
> replace your process, this means it will not continue your program. To
> get arround this you find that people will first fork()[2] and exec on
> the child process.

Ah yes. Threads are all part of the same process, so you have to fork rather 
than create a new thread. Whoops. I should have thought of that. But I guess 
that comes from my almost never using fork and even only using threads when 
I have to. Of course, it would be nice if there were a function in phobos to 
abstract that out, but there's enough work to do on phobos that that's 
probably not at the top of the list by any means.

> 
> In order to get your standard output you would use the dup2()[3] call.
> 
> Please note that I do not know how any of this will related to practices
> on Windows. And sadly this is not D specific and actually C stuff.
> 
> 1. http://www.opengroup.org/onlinepubs/007908799/xsh/exec.html
> 2. http://www.yolinux.com/TUTORIALS/ForkExecProcesses.html
> 3. http://www.mkssoftware.com/docs/man3/dup2.3.asp

Well, it's good info. So, thanks. But it would be nice if that too were 
nicely abstracted in phobos. The undocumented shell() command works, but it 
uses the shell, so you have to worry about escaping characters. Bleh. In any 
case, thanks for the info.

- Jonathan M Davis