On 17 Dec 14, at 19:27, Dave Parsons wrote:
Hi Dave, > I needed to create an OS/2 DLL today & was disappointed by the compiler > (v2.6.4) telling me that they were not supported. > > http://www.freepascal.org/faq.var#os2-dll section 6.3 seems to agree but is > rather old. > > Can anyone confirm that this is still true? Yes, it's still the case. > Google didn't find much and it is not mentioned on the Future Plans page. > What is the reason? > Too difficult, no demand/request, no time or whatever. The primary reason is the fact that creation of DLLs is not supported by the ancient EMX port of the GNU linker ld.exe. As far as I know, OS/2 ports of GCC (both the original EMX port and the recent ones) solve this issue by using the IBM linker (possibly masked by EMXOMFLD binary). However, this has several caveats (no special order): 1) Object files need to be translated/transformed from the a.out format supported by the GNU binutils (as.exe and ld.exe) to Intel OMF expected by the IBM linker (e.g. using the tool EMXOMF supplied with EMX), or they need to be assembled using a different assembler supporting this format (such as Watcom assembler or NASM) from the very beginning, or support for direct creation of object files in this format needs to be added to FPC directly. When I tried translating object files created by FPC (using as.exe) with EMXOMF some time ago, it failed to process some of them. I didn't manage to find out the reasons so that I could possibly fix them at that point in time (no we get to amount of time available mentioned by you). 2) Binaries linked with IBM LINK.EXE cannot be debugged using GDB/PMGDB any longer (and no other debugger either, in fact, because LINK.EXE would not support the stabs debug format which is currently the only alternative supported for the OS/2 target in FPC). 3) There are certain special features which would need to be solved differently if using a different linker (e.g. support for direct port access). These wouldn't prevent most common uses, but they would require spending some time on their resolution too. Now back to your questions: 1) Is it possible to solve it? Yes, certainly. 2) Does the resolution require considerable amount of time? Yes, it probably does (especially if the only person working on it is me). 3) Has there been strong demand? Well, not really (although some questions already arose in the past). I don't have much time for working on this task, but I'm willing to spend some time on it as soon as I finish my current work on finally properly supporting all UnicodeString Manager functions for OS/2 (that requires some time, but it is quite simple from technical point of view). My motivation to work on the linker issue would be higher if someone else joins me in this effort. Feel free to contact me directly if you're interested. Tomas _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
