Problems using GetEnvironmentVariable

[carl_caulkett]

Hello, I am trying to use the SysUtils function GetEnvironmentVariable in an LCL GUI Application, but the function always returns #0. Yet, if I use the function in a simple console application, it returns the correct value. Can anyone help?

[JuhaManninen]

Can anyone help?

Not without example code.

[carl_caulkett]

Okay...

This works:

Code: Pascal  [Select][+][-]

1. program envvar_console;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   {$IFDEF UNIX}{$IFDEF UseCThreads}
7.   cthreads,
8.   {$ENDIF}{$ENDIF}
9.   Classes,
10.   SysUtils
11.   { you can add units after this };
12.  
13. var
14.   v: string;
15. begin
16.   v := GetEnvironmentVariable('GOPATH');
17.   WriteLn(v);
18. end.
19.  

           

and this doesn't:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     Button1: TButton;
16.     Label1: TLabel;
17.     procedure Button1Click(Sender: TObject);
18.   private
19.   public
20.     { public declarations }
21.   end;
22.  
23. var
24.   Form1: TForm1;
25.  
26. implementation
27.  
28. {$R *.lfm}
29.  
30. { TForm1 }
31.  
32. procedure TForm1.Button1Click(Sender: TObject);
33. var
34.   S: string;
35. begin
36.   S := SysUtils.GetEnvironmentVariable('GOPATH');
37.   Label1.Caption := S;
38. end;
39.  
40. end.                                    
41.  

The project options are set to default in both cases.

Thanks in advance for any help.

[JuhaManninen]

The code looks correct. It means the actual environment is different. Maybe it depends on how you start the application. From console / desktop etc.
You did not mention your OS but I assume Windows.

[jwdietrich]

The code looks correct. It means the actual environment is different. Maybe it depends on how you start the application. From console / desktop etc.
You did not mention your OS but I assume Windows.

The question is in the subforum "Mac OS X", therefore I think it refers to macOS.

[jwdietrich]

Hello, I am trying to use the SysUtils function GetEnvironmentVariable in an LCL GUI Application, but the function always returns #0. Yet, if I use the function in a simple console application, it returns the correct value. Can anyone help?

Are you sure that the GOPATH environment variable is globally set?

If I use your code with other environment variables, e. g. USER, it works correctly, even in an LCL app.

[carl_caulkett]

I'm running Lazarus 1.6.4 + FPC 3.0.2 on macOS 10.12.5 Sierra

I'm building both apps within Lazarus. The command line app works when run both within Lazarus and from the command line. I have only tried the GUI app from within Lazarus.

[jwdietrich]

I'm running Lazarus 1.6.4 + FPC 3.0.2 on macOS 10.12.5 Sierra

I'm building both apps within Lazarus. The command line app works when run both within Lazarus and from the command line. I have only tried the GUI app from within Lazarus.

Did you try the code with the USER environment variable?

[carl_caulkett]

The code looks correct. It means the actual environment is different. Maybe it depends on how you start the application. From console / desktop etc.
You did not mention your OS but I assume Windows.

The question is in the subforum "Mac OS X", therefore I think it refers to macOS.

Well spotted 

[carl_caulkett]

I'm running Lazarus 1.6.4 + FPC 3.0.2 on macOS 10.12.5 Sierra

I'm building both apps within Lazarus. The command line app works when run both within Lazarus and from the command line. I have only tried the GUI app from within Lazarus.

Did you try the code with the USER environment variable?

Hmmm... I've just tried with the USER environment variable and that works in both cases. There must be something odd about the GOPATH variable.

[JuhaManninen]

The question is in the subforum "Mac OS X", therefore I think it refers to macOS.

Ooops, sorry. My bad.
I don't know much about macOS.

[jwdietrich]

Just for fun, I have made a mini project that shows the contents of arbitrary environment variables as read by the LCL. It works well on macOS (and probably any other platform). See attachment.

Unlike your code, it uses the function GetEnvironmentVariableUTF8 from the LazUTF8 unit. You have to add LazUTF8 in the uses section of your code.

[carl_caulkett]

I'm running Lazarus 1.6.4 + FPC 3.0.2 on macOS 10.12.5 Sierra

I'm building both apps within Lazarus. The command line app works when run both within Lazarus and from the command line. I have only tried the GUI app from within Lazarus.

Did you try the code with the USER environment variable?

Hmmm... I've just tried with the USER environment variable and that works in both cases. There must be something odd about the GOPATH variable.

The GOPATH environment variable is defined in the fish.config file for the Fish shell that I am using for Golang development.

It is defined with the following line:

set -x GOPATH $HOME/Code/go

This all happens at the shell level. It seems odd that the variable is available in the console app but not the GUI app. I would have thought it would be an "All or nothing" type situation. Presumably, the GetEnvironmentVariable function is behaving differently in the different environments. The situation is made more difficult by the problems inherent in debugging in Lazarus on the Apple Mac, although I know that Xcode can be used - it's just a bit fiddly!

[carl_caulkett]

Just for fun, I have made a mini project that shows the contents of arbitrary environment variables as read by the LCL. It works well on macOS (and probably any other platform). See attachment.

Unlike your code, it uses the function GetEnvironmentVariableUTF8 from the LazUTF8 unit. You have to add LazUTF8 in the uses section of your code.

I've tried your project and while it works for environment variables such as USER and PATH, it doesn't work for GOPATH. Presumably, the GOPATH variable is not a "Proper" environment variable, though what does actually constitute a "Proper" environment variable is beyond me.

I may have to risk humiliation and consult the almighty beings of StackOverflow in order to find out, though I was hoping to keep things within the warm and cosy confines of the Lazarus forums!

[jwdietrich]

The difference may result from the fact that you launch CLI applications made with FPC from the shell, but GUI applications based on the LCL from the Finder.

For permanent storage of Environment variables, macOS uses two approaches: Environment variables for use by the shell and CLI programs are stored in ~/.bash_profile (you may want to type more ~/.bash_profile to display the current contents of this file on your computer), while environment variables for GUI applications are stored in ~/.MacOSX/environment.plist (for Mac OS X Lion and Mountain Lion only) or in /etc/launchd.conf (for newer versions of macOS).

Additionally, the syntax is slightly different: In ~/.bash_profile the environment variables are set with

Code: Bash  [Select][+][-]

1. export PATH=$PATH:/Library/PostgreSQL/8.4/bin

but with

Code: Bash  [Select][+][-]

1. setenv JRUBY_HOME /Applications/Dev/jruby

in /etc/launchd.conf.