How can I redirect stdout / stderr to file (from D not shell)?

On Wednesday, 11 April 2012 at 12:46:30 UTC, Andrea Fontana wrote:
> How can I redirect stdout / stderr to file (from D not shell)?

Self-reply:

It works using std.c way:

import std.cstream;
std.c.stdio.freopen(args[4].ptr, "w+", dout.file);
std.c.stdio.freopen(args[4].ptr, "w+", derr.file);

On Wednesday, 11 April 2012 at 13:00:45 UTC, Andrea Fontana wrote:
> On Wednesday, 11 April 2012 at 12:46:30 UTC, Andrea Fontana wrote:
>> How can I redirect stdout / stderr to file (from D not shell)?
>
> Self-reply:
>
> It works using std.c way:
>
> import std.cstream;
> std.c.stdio.freopen(args[4].ptr, "w+", dout.file);
> std.c.stdio.freopen(args[4].ptr, "w+", derr.file);

Careful: D strings are not zero-terminated. args[4].toStringz() is the safer choice.

Cheers,
Stefan

On Wednesday, 11 April 2012 at 15:25:56 UTC, Stefan wrote:
> On Wednesday, 11 April 2012 at 13:00:45 UTC, Andrea Fontana wrote:
>> On Wednesday, 11 April 2012 at 12:46:30 UTC, Andrea Fontana wrote:
>>> How can I redirect stdout / stderr to file (from D not shell)?
>>
>> Self-reply:
>>
>> It works using std.c way:
>>
>> import std.cstream;
>> std.c.stdio.freopen(args[4].ptr, "w+", dout.file);
>> std.c.stdio.freopen(args[4].ptr, "w+", derr.file);
>
> Careful: D strings are not zero-terminated. args[4].toStringz() is the safer choice.
>
> Cheers,
> Stefan

Good point Stefan!

On Thursday, 12 April 2012 at 08:11:58 UTC, Andrea Fontana wrote:
> On Wednesday, 11 April 2012 at 15:25:56 UTC, Stefan wrote:
>> On Wednesday, 11 April 2012 at 13:00:45 UTC, Andrea Fontana wrote:
>>> On Wednesday, 11 April 2012 at 12:46:30 UTC, Andrea Fontana wrote:
>>>> How can I redirect stdout / stderr to file (from D not shell)?
>>>
>>> Self-reply:
>>>
>>> It works using std.c way:
>>>
>>> import std.cstream;
>>> std.c.stdio.freopen(args[4].ptr, "w+", dout.file);
>>> std.c.stdio.freopen(args[4].ptr, "w+", derr.file);
>>
>> Careful: D strings are not zero-terminated. args[4].toStringz() is the safer choice.
>>
>> Cheers,
>> Stefan
>
> Good point Stefan!

why not:
import std.stdio;
stdout = File(args[4], "w+");
stderr = File(args[4], "w+");

On Sunday, 12 April 2015 at 04:39:06 UTC, Philip Stuckey wrote:
> why not:
> import std.stdio;
> stdout = File(args[4], "w+");
> stderr = File(args[4], "w+");

It just replaces the object, not redirects output. E.g. if you use printf somewhere it will use stdout, not file.

On 13/04/2015 1:12 a.m., FreeSlave wrote:
> On Sunday, 12 April 2015 at 04:39:06 UTC, Philip Stuckey wrote:
>> why not:
>> import std.stdio;
>> stdout = File(args[4], "w+");
>> stderr = File(args[4], "w+");
>
> It just replaces the object, not redirects output. E.g. if you use
> printf somewhere it will use stdout, not file.

You will need to use writefln instead of printf. As printf uses the processes stdout. Changing this would be tricky and OS based.