How to set environnement strings in Pascal?

Well, at least in Turbo Pascal there was (if I recall correctly)
a function called SetEnv that allowed you to set environment
variables. Could be that there was only GetEnv, but I think I
have used SetEnv sometime.

Thanx for responding, but the SetEnv works only with Turbo Pascal for Windows (or with BP for Windows target) not for DOS...

Bye

Try using the swapvectors procedure to call Dos commands from your program.

As an example:

SwapVectors;
Exec(GetEnv('COMSPEC','/c'+Command));
SwapVectors;

Where Command is some DOS Command string.  Hope this helps

To retrieve all the DOS environment variables use :

var i: Integer;

begin
   for i := 1 to EnvCount do
      WriteLn(EnvStr(i));
end;

This will return all your environment strings set in DOS.  If you are searching for just one string, use :

const SString = 'PATH'; {or any other string}

var Found: Boolean;
        i: String;

begin
   i := 0;
   Found := False;
   While (I < EnvCount) and (Not Found) do
      Found := (Pos(SString, EnvStr(I)) > 0);
end;

As DOS Env. strings are uppercase, ensure you use an uppercase search string, otherwise this routine wont find what you are looking for.

Hope this helps.


Stuart

Thanx... But this is to read environnement strings, not to write them!

I seem to remember using SetEnv to set a DOS Envirnment variable.
The only problem I found was that the variable didn't stay when
the program exited - it was a local environment variable to the
program.

Sorry about the last response I left.  I didnt really read the question properly.  Anyway, I think this will solve all you problems.

Function SetEnvStr(Env : EnvRec; Search, Value : String) : Boolean;
Var
  SLen : Byte Absolute Search;
  VLen : Byte Absolute Value;
  EPtr : EnvArrayPtr;
  ENext : Word;
  EOfs : Word;
  MOfs : Word;
  OldLen : Word;
  NewLen : Word;
  NulLen : Word;
begin
  With Env do begin
    SetEnvStr := False;
    if (EnvSeg = 0) or (SLen = 0) then
      Exit;
    EPtr := Ptr(EnvSeg, 0);

    {Find the search String}
    EOfs := SearchEnv(EPtr, Search);

    {Get the index of the next available environment location}
    ENext := EnvNext(EPtr);

    {Get total length of new environment String}
    NewLen := SLen+VLen;

    if EOfs <> $FFFF then begin
      {Search String exists}
      MOfs := EOfs+SLen;
      {Scan to end of String}
      SkipAsciiZ(EPtr, MOfs);
      OldLen := MOfs-EOfs;
      {No extra nulls to add}
      NulLen := 0;
    end else begin
      OldLen := 0;
      {One extra null to add}
      NulLen := 1;
    end;

    if VLen <> 0 then
      {Not a pure deletion}
      if ENext+NewLen+NulLen >= EnvLen+OldLen then
        {New String won't fit}
        Exit;

    if OldLen <> 0 then begin
      {OverWrite previous environment String}
      Move(EPtr^[MOfs+1], EPtr^[EOfs], ENext-MOfs-1);
      {More space free now}
      Dec(ENext, OldLen+1);
    end;

    {Append new String}
    if VLen <> 0 then begin
      Move(Search[1], EPtr^[ENext], SLen);
      Inc(ENext, SLen);
      Move(Value[1], EPtr^[ENext], VLen);
      Inc(ENext, VLen);
    end;

    {Clear out the rest of the environment}
    FillChar(EPtr^[ENext], EnvLen-ENext, 0);

    SetEnvStr := True;
  end;
end;


Regards,


Stuart

Thanx, I will try this tomorrow.....