[fpc-pascal]How to get the Home Directory of the user? (using pchar correctly)

[Stefan Becker]

Hi,
just by quickly looking at the example you gave I would say that
you pass pointers to the memory areas where the results
should be returned, but never declare the accual memory.

if you pass a pchar type - meaning a "pointer to a area of char memory".
Then this memory must be valid.

I would declare something like:

{$PACKRECORDS 4}
Type
   pPasswd = ^passwd;
   passwd  = Record
      pw_name,                         { Username }
      pw_passwd : pChar;        { Password }
      pw_uid,                              { User ID }
      pw_gid : longint;                { Group ID }
      pw_gecos,                         { Real Name }
      pw_dir,                               { Home directory }
      pw_shell : pChar;              { Shell program }
   End;

var
pwd : pPasswd;
userdata:array[0..255] of char;
user: pChar;

BEGIN
user:=@userdata;
........
now your progi could work!!


Stefan





-----Ursprüngliche Nachricht-----
Von: Hélio Cavichiolo Jr <helio at definitylinux.com.br>
An: fpc-pascal at deadlock.et.tudelft.nl <fpc-pascal at deadlock.et.tudelft.nl>
Datum: Freitag, 6. September 2002 19:10
Betreff: Re: [fpc-pascal]How to get the Home Directory of the user?


>How to check if a call to getpwnam had success?
>How to change user information?
>
>I made this program to test but the 'if' never matches.
>Entering a valid user, I had to remove de 'if' to see user's gecos, by the
>other hand, entering an invalid user, the program crashes on the 'if'.
>
>program test;
>
>uses
>  pwdlibc;
>
>var
>  pwd : pPasswd;
>  user: pChar;
>
>begin
>  user := '';
>  write('Usuário: ');
>  readln(user);
>  pwd := Getpwnam(user);
>  if user = pwd^.pw_name then
>    begin
>      writeln('(',pwd^.pw_name,')');
>      writeln('(',pwd^.pw_gecos,')');
>    end
>  else
>    writeln(user,' not found!');
>end.
>
>> Hi,
>> this is how you can get some info's from a logged User:
>>
>> unit pwdlibc;
>>
{---------------------------------------------------------------------------
>>                                  CncWare
>>                             (c) Copyright 1999
>> -------------------------------------------------------------------------
---
>>   Filename..: pwdlibc.pp
>>   Programmer: Ken J. Wright
>>   Date......: 10/01/1999
>>
>>   Purpose - Link to the Linux 'c' library for system passwd functions.
>>
>> -------------------------------< Revisions
>>>---------------------------------
>> Revision|   Date   | Prog| Description
>> -------------------------------------------------------------------------
---
>> -
>> 1.00    | 10/01/99 | kjw | Initial release.
>> -------------------------------------------------------------------------
---
>> -
>> }
>>
>> interface
>>
>> {$linklib c}
>>
>> {$PACKRECORDS 4}
>> Type
>>    pPasswd = ^passwd;
>>    passwd  = Record
>>       pw_name,                         { Username }
>>       pw_passwd : pChar;               { Password }
>>       pw_uid,                          { User ID }
>>       pw_gid : longint;                { Group ID }
>>       pw_gecos,                        { Real Name }
>>       pw_dir,                          { Home directory }
>>       pw_shell : pChar;                { Shell program }
>>    End;
>>
>>    pGroup = ^group;
>>    group  = Record
>>       gr_name,                         { Group name }
>>       gr_passwd : pChar;               { Password }
>>       gr_gid : longint;                { Group ID }
>>       gr_mem : pChar;                  { Member list }
>>    End;
>>
>> { returns a pointer to a passwd record }
>> Function getpwuid(uid : longint) : pPasswd; cdecl;
>> Function getpwnam(nam : pChar) : pPasswd; cdecl;
>>
>> { returns a pointer to a group record }
>> Function getgrgid(gid : longint) : pGroup; cdecl;
>> Function getgrnam(nam : pChar) : pGroup; cdecl;
>>
>> implementation
>>
>> Function getpwuid(uid : longint) : pPasswd; cdecl; External;
>> Function getpwnam(nam : pChar) : pPasswd; cdecl; External;
>> Function getgrgid(gid : longint) : pGroup; cdecl; External;
>> Function getgrnam(nam : pChar) : pGroup; cdecl; External;
>>
>> end.
>>
>> my regards,
>> Stefan
>>
>>
>>
>>>Hello, Every body
>>>
>>>  Can you tell me how to get the Home Directory of a user in free
>>> pascal
>> under
>>>linux? Thank you very much.
>>>
>>>  Yours,
>>>  mili
>>
>>
>>
>>
>>
>> _______________________________________________
>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>> http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>
>
>--
>Helio Cavichiolo Jr
>Analista de Sistemas
>Esc Telecomunicações Ltda
>D e f i n i t y   L i n u x
>
>
>
>_______________________________________________
>fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>