TEAM-ADA Archives

Team Ada: Ada Programming Language Advocacy


Options: Use Classic View

Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Topic: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Steffen Bretz <[log in to unmask]>
Tue, 20 Apr 1999 01:06:32 -0700
text/plain (71 lines)
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

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

(The function is somewhat complicated but simply typing
    return To_Ada (C_Env (To_C (Name)));
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