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Sender: "Team Ada: Ada Advocacy Issues (83 & 95)" <[log in to unmask]>
From: Steffen Bretz <[log in to unmask]>
Date: Tue, 20 Apr 1999 01:06:32 -0700
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Reply-To: Steffen Bretz <[log in to unmask]>
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Hello team members!

I have subscribed this list some times ago and now this is my first
contribution to it.

Until now I have programmed in Ada83 and needed some non-portable
packages to access command line arguments and environment variables.

Now I have an Ada95 compiler (gnat) on my new Linux machine. The
Ada95 standard contains a package Ada.Command_Line which gives my
programs access to command line arguments - but not to environment
variables.

I did not found any way to give my programs access to these
variables. Have I overlooked something or is there no way?

I tried to interface to the C function getenv. The interface seems
to work but getenv only returns my input (the name of the variable
but not their contents):

  function Get_Environment_Variable (Name: String) return String is

    -- NAME:
    --   getenv - get an environment variable
    -- SYNOPSIS:
    --   #include <stdlib.h>
    --   char *getenv(const char *name);
    -- DESCRIPTION:
    --   The  getenv() function searches the environment list for a
    --   string that matches the string pointed to by name. The
    --   strings are of the form name = value.

    package C renames Interfaces.C;

    function Getenv (Name: in C.char_array) return C.char_array;
    pragma Import (C, Getenv, "getenv");

    C_Name: C.Char_Array (0 .. Name'Length);
    Env_Length: Natural;

    use C;
  begin
    C_Name := To_C (Name);
    Env_Length := Getenv (C_Name)'Length - 1;
    declare
      C_Env: C.Char_Array (0 .. C.size_t (Env_Length));
    begin
      C_Env (0) := C.nul;
      C_Env := Getenv (C_Name);
      return To_Ada (C_Env);
    end;
  end;

(The function is somewhat complicated but simply typing
  ...
  begin
    return To_Ada (C_Env (To_C (Name)));
  end;
produces a "segmentation fault".)


Has anybody a solution for my problem?


Sorry for my broken english :)
====================================================================
Steffen Bretz                     Tel +49-561-7392805
Rothenditmolder Str. 23           mailto:[log in to unmask]
34117 Kassel
Germany

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