Hi,

Is it possible to change the current process's environment variables?

I have looked at `std/process.d` source code, and there is only a private method `createEnv` used when new (sub)process is created.

In C `putEnv` the answer is positive: http://man7.org/linux/man-pages/man3/putenv.3.html (FIXME)

I come to this question as I want to set some custom variables for my unittests. My program reads some tokens from system environments, and it's convenient if I can simulate different cases for testings.

Thanks for your reading and support.

Ky-Anh Huynh wrote:

> Hi,
>
> Is it possible to change the current process's environment variables?
>
> I have looked at `std/process.d` source code, and there is only a private method `createEnv` used when new (sub)process is created.
>
> In C `putEnv` the answer is positive: http://man7.org/linux/man-pages/man3/putenv.3.html (FIXME)
>
> I come to this question as I want to set some custom variables for my unittests. My program reads some tokens from system environments, and it's convenient if I can simulate different cases for testings.
>
> Thanks for your reading and support.

you can use libc's `putenv()` in D too, it is ok. just import `core.sys.posix.stdlib`,  it is there. D is not antagonistic to C, and doesn't try to replace the whole libc with it's own libraries. so if you see something that libc has and you'd like to use -- just do it! ;-)

On Tuesday, 17 October 2017 at 04:56:23 UTC, ketmar wrote:
>
> you can use libc's `putenv()` in D too, it is ok. just import `core.sys.posix.stdlib`,  it is there. D is not antagonistic to C, and doesn't try to replace the whole libc with it's own libraries. so if you see something that libc has and you'd like to use -- just do it! ;-)

I see :) I have always tried to avoid C if possible :D

On Tuesday, 17 October 2017 at 05:57:50 UTC, Ky-Anh Huynh wrote:
> On Tuesday, 17 October 2017 at 04:56:23 UTC, ketmar wrote:
>>
>> you can use libc's `putenv()` in D too, it is ok. just import `core.sys.posix.stdlib`,  it is there. D is not antagonistic to C, and doesn't try to replace the whole libc with it's own libraries. so if you see something that libc has and you'd like to use -- just do it! ;-)
>
> I see :) I have always tried to avoid C if possible :D

As an alternative, a search on code.dlang.org turned up this lib:

http://code.dlang.org/packages/dotenv

On 2017-10-17 06:51, Ky-Anh Huynh wrote:
> Hi,
> 
> Is it possible to change the current process's environment variables?
> 
> I have looked at `std/process.d` source code, and there is only a private method `createEnv` used when new (sub)process is created.
> 
> In C `putEnv` the answer is positive: http://man7.org/linux/man-pages/man3/putenv.3.html (FIXME)
> 
> I come to this question as I want to set some custom variables for my unittests. My program reads some tokens from system environments, and it's convenient if I can simulate different cases for testings.
> 
> Thanks for your reading and support.

Use std.process.environment [1] and assign to it like an associative array.

[1] https://dlang.org/phobos/std_process.html#.environment.opIndexAssign

-- 
/Jacob Carlborg

On Tuesday, 17 October 2017 at 11:49:32 UTC, Jacob Carlborg wrote:
> On 2017-10-17 06:51, Ky-Anh Huynh wrote:
>> Hi,
>> 
>> Is it possible to change the current process's environment variables?
>> 
>> I have looked at `std/process.d` source code, and there is only a private method `createEnv` used when new (sub)process is created.
>> 
>> In C `putEnv` the answer is positive: http://man7.org/linux/man-pages/man3/putenv.3.html (FIXME)
>> 
>> I come to this question as I want to set some custom variables for my unittests. My program reads some tokens from system environments, and it's convenient if I can simulate different cases for testings.
>> 
>> Thanks for your reading and support.
>
> Use std.process.environment [1] and assign to it like an associative array.
>
> [1] https://dlang.org/phobos/std_process.html#.environment.opIndexAssign

Oh thanks a lot for your pointing out, Jacob. That's the thing I'm looking for. The C version is not so bad though

```
  import core.sys.posix.stdlib;
  import std.string: toStringz;

  string jenkinsToken = "TEST_TOKEN=";
  putenv(cast(char*)jenkinsToken);
```

On Tuesday, 17 October 2017 at 08:42:09 UTC, Rene Zwanenburg wrote:
> On Tuesday, 17 October 2017 at 05:57:50 UTC, Ky-Anh Huynh wrote:
>> On Tuesday, 17 October 2017 at 04:56:23 UTC, ketmar wrote:
>>>
>>> you can use libc's `putenv()` in D too, it is ok. just import `core.sys.posix.stdlib`,  it is there. D is not antagonistic to C, and doesn't try to replace the whole libc with it's own libraries. so if you see something that libc has and you'd like to use -- just do it! ;-)
>>
>> I see :) I have always tried to avoid C if possible :D
>
> As an alternative, a search on code.dlang.org turned up this lib:
>
> http://code.dlang.org/packages/dotenv

Awesome. I will take a look definitely. I have a similar way in my NodeJS team :D