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digitalmars.D.learn - std.process.execute without capturing stderr?

reply berni <someone somemail.de> writes:
I need to execute a program and capture stdout, which I hoped 
std.process.execute would do. But unfortunatly this command also 
captures stderr, which I need to be ignored. When looking at the 
implementation of std.process.execute I see, that I can probably 
do this by removing "Redirect.stderrToStdout" in the function 
executeImpl. But for that I have to copy lots of functions from 
phobos in my own code. Is there an easier way to do that?

In case you wonder why I need this: I'm currently using a PHP 
frontend and a D backend. I'm calling the D routines with the PHP 
exec command which works fine, but unfortunately removes trailing 
whitespaces, that I need. Therefore I'd like to have a wrapper 
that replaces all whitespace by some escape sequences which than 
are restored in PHP. First I thought I can use sed for that, but 
unfortunately the return code gets lost here. I'm using stderr to 
show some progress information, which should be shown 
immediately. (I've you've got other ideas how to get arround this 
design flaw (as I see it) in php exec, I'd be happy too.)

I don't want to touch the D backend - that's not the place, where 
the problem lies and when I decide to change the frontend I've to 
remember to change the backend too, which I don't like.

Here my complete program:


 import std.process;
 import std.stdio;
 import std.array;
 
 int main(string[] args)
 {
     const result = execute(args[1..$]);
     writeln(result[1].replace("\\","\\\\").replace(" ","\\s"));
     return result[0];
 }
Sep 20 2018
parent reply Paul Backus <snarwin gmail.com> writes:
On Thursday, 20 September 2018 at 07:24:52 UTC, berni wrote:

 I need to execute a program and capture stdout, which I hoped 
 std.process.execute would do. But unfortunatly this command 
 also captures stderr, which I need to be ignored. When looking 
 at the implementation of std.process.execute I see, that I can 
 probably do this by removing "Redirect.stderrToStdout" in the 
 function executeImpl. But for that I have to copy lots of 
 functions from phobos in my own code. Is there an easier way to 
 do that?

 [...]

 Here my complete program:


 import std.process;
 import std.stdio;
 import std.array;
 
 int main(string[] args)
 {
     const result = execute(args[1..$]);
     writeln(result[1].replace("\\","\\\\").replace(" ","\\s"));
     return result[0];
 }




Looks like `Config.stderrPassThrough` [1] should do what you want:

     const result = execute(args[1..$], null, 
Config.stdErrPassThrough);

[1] 
https://dlang.org/phobos/std_process.html#.Config.stderrPassThrough
Sep 20 2018
parent reply berni <someone somemail.de> writes:
On Thursday, 20 September 2018 at 07:36:06 UTC, Paul Backus wrote:

 Looks like `Config.stderrPassThrough` [1] should do what you 
 want:

     const result = execute(args[1..$], null, 
 Config.stdErrPassThrough);

 [1] 
 https://dlang.org/phobos/std_process.html#.Config.stderrPassThrough


In theory that looks good. Unfortunatley it's a relativly young 
feature which my compilers don't know about yet (dmd 2.079 and 
ldc based on an even older version of dmd). So in practice I'll 
probably have to wait until the next release cycle of debian in 
spring 2019... (maybe for the time being I'll update dmd and use 
dmd for this small part instead of ldc, but I yet don't know how 
to tell CMake to use dmd for this one file... But I'll probably 
figure this out.)
Sep 20 2018
parent reply Steven Schveighoffer <schveiguy gmail.com> writes:
On 9/20/18 4:02 AM, berni wrote:

 On Thursday, 20 September 2018 at 07:36:06 UTC, Paul Backus wrote:

 Looks like `Config.stderrPassThrough` [1] should do what you want:

     const result = execute(args[1..$], null, Config.stdErrPassThrough);

 [1] https://dlang.org/phobos/std_process.html#.Config.stderrPassThrough


 
 In theory that looks good. Unfortunatley it's a relativly young feature 
 which my compilers don't know about yet (dmd 2.079 and ldc based on an 
 even older version of dmd). So in practice I'll probably have to wait 
 until the next release cycle of debian in spring 2019... (maybe for the 
 time being I'll update dmd and use dmd for this small part instead of 
 ldc, but I yet don't know how to tell CMake to use dmd for this one 
 file... But I'll probably figure this out.)
 


Hm... 2.079.0 had it:

https://docarchives.dlang.io/v2.079.0/phobos/std_process.html#.Config.stderrPassThrough

I don't know what your "older version of dmd" was, but the earliest I 
can see it is 2.077.0.

Indeed, it was fixed in 2.077 (look for Bugzilla 17844 here: 
https://dlang.org/changelog/2.077.0.html)

-Steve
Sep 20 2018
parent reply berni <someone somemail.de> writes:
On Thursday, 20 September 2018 at 14:10:44 UTC, Steven 
Schveighoffer wrote:

 Hm... 2.079.0 had it:


Sorry, I made a mistake while testing and after I found out, that 
it was not available in the documentation at dpldocs.info I 
concluded, that it must be a really new feature. But now it seems 
to me, that dpldocs is outdated a little bit, isn't it?

Meanwhile I've got the latest version of dmd and made it working.
Sep 20 2018
parent Adam D. Ruppe <destructionator gmail.com> writes:
On Friday, 21 September 2018 at 06:08:39 UTC, berni wrote:

 Sorry, I made a mistake while testing and after I found out, 
 that it was not available in the documentation at dpldocs.info 
 I concluded, that it must be a really new feature. But now it 
 seems to me, that dpldocs is outdated a little bit, isn't it?


Oh yeah, I haven't updated Phobos on it for a while, my attention 
most this year has been the dub thingy. Just did though.
Sep 21 2018