Using ICS under Free Pascal

What is ICS?

ICS (Internet Component Suite), is a set Delphi classes for TCP/IP based communications using the usual internet protocols. There is also a version for Kylix.

ICS and the middleware suite Midware are available on the Overbyte site (click the logo in the top left of this page)

FPC Compiler version

I use (and you'll need) FPC compiler: 1.9.8. Maybe 1.9.6 works too. This is for Windows. Other OSes (most notably Linux and FreeBSD) and FPC versions (1.0.x) are not yet supported.

The above compiler date is not fixed, if compability issues are found and fixed, it might increase.

The 1.9.x series is used because that minimizes the changes to ICS. All changes at this point have been absorbed into the ICS distribution by Francois.

It might be possible to do a different port of ICS to 1.0.10, but I don't think it is wise to merge these fixes in to Francois' main distribution.

Noforms

Quite some of the changes for FPC were actually patches to the console application (non forms.application event loop) support of ICS. Francois made a nice unit for this, called conapp that eases this.

ICS version

Currently I use Francois releases of early march 2005. No modifications on the FPC runtime were needed, and the ICS distribution con* applications should compile directly with FPC 1.9.8.

Types

1. units that compile right away with FPC 1.9.8, with only the "general" changes described belowand maybe a few very small detail fixes (see "per file") and can be tested using one of the con files
2. same 1, but can't be tested because there is no console demo yet
3. units that use forms, but only for (de)allocatehwnd and/or the application object. (see "dummy forms" paragraph) (tncnx, pop3prot, nntpcli and ftpsrv )
4. Heavily VCL using units that define controls. (tnoptfrm emulvt, wait and pop3cli use forms heavily. tnemulvt uses emulvt)

As said category 1 and 2 only need the "general" fixes listed below, and a few "per unit" fixes.

Category 3 could also work, but needs some things adapted in the eventflow. It turned out that Francois was already working on this (wsocket.allocatehwnd), and pop3prot and ftpsrv are working. nttpcli was fixed, but there is no demo for it yet.

Category 4 Maybe (partially?) portable to lazarus in say a year time, but I don't touch them for now. See separate lazarus section

General changes needed

These more intrusive changes are needed in every unit (and a lot of the relevant demoes). Most involve preprocessor or uses clause fixes. The only units that don't qualify are units that really _use_ the visual part of the VCL, and have nothing else, (tnoptfrm, emulvt, wait and pop3cli. tnemulvt is based on emulvt. Most demoes)

• A global include file (I called it icsdef.inc) included in each unit or console capable demo, the right spot is after the interface or program keyword. The FPC specific part of this file puts FPC into delphi mode and sets USEWINDOWS and NOFORMS:

  {$ifdef FPC}
  {$MODE Delphi}                           // delphi mode
  {$asmmode Intel}                         // Intel syntax assembler
  {$define usewindows}                     // Use "Windows" unit.
  {$define Noforms}                        // No unit forms.
  {$define socketulongmustmatch}		 // not used yet.
  {$endif}
  

• The define USEWINDOWS (set in the includefile above) forces the unit to use the windows unit instead of the (AFAIK) TPW/D1 units wintypes and winprocs. FPC supports 32-bit Delphi only.
  This affects nearly all "uses" clauses AND a few occurances of qualification of identifiers with unitnames:

       {$Ifdef usewindows}Windows, {$else}WinTypes, WinProcs, {$endif}
       

• Introduce noforms check everywhere as much as possible (forms,controls,graphics etc) except for units that actually define only controls (category 4). Examples enough already in the source.
• (minor) Some of the comments braces in the unit description (the large comment which is first in each unit) need to be balanced like in TP this because only the icsdef.inc at the "interface" keyword puts FPC in Delphi mode. (about 2 or 3 occurances)

unit specific changes

• wsocket Passing a longint as a (reference) parameter to a procedure that defines the parameter as "var u : u_long" doesn't. work.This is because ulong is a longword in FPC, and FPC 1.1 is strict about this (a longword's range doesn't fit into a int64) Maybe fixable by simply adding the following to wsocket.pas near the top.

  	{$ifdef FPC}
  	type u_long=longint;
   	{$endif}
  	

• mbxfile had a lines 329 and 332 fixed; NewPos + p - Buf - 3 must become NewPos + (p - Buf) - 3 (the other case is similar) This is a FPC bug, but the fix doesn't matter for Delphi, and makes life easier for time being.

Status

Main units

1. conapp
2. dnsquery
3. fingcli
4. ftpcli
5. ftpsrvc ftpsrvt and ftpsrv
6. httpprot and httpsrv
7. icmp