Re: [fpc-pascal] Re: Object Files
On Mon, Jul 18, 2011 at 2:07 PM, leledumbo wrote: >> Are object files platform dependent? > > No >From the rest of your post I guess you mean "yes, they are dependent"? > >> Something tells me they ARE platform independent since they have to be >> linked in. > > Pardon me? That seems unrelated. Object files are basically executables with > external symbols unresolved and no starting point, do you think executables > platform independent? > He's asking exactly this. If there was no difference in calling conventions and every access to the OS was through the RTL it could be cross-platform in this sense (since he's changing the OS but not the processor/architecture). -Flávio ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: Object Files
On 18.07.2011 19:07, leledumbo wrote: Are object files platform dependent? No Depending on the context the author thought in this could have been answered with "yes, mostly" as well: You can't use object files from x86 on ARM or from Windows on Linux (in the sense of using the object file from the other platform and trying to link and run it on this platform (without emulation)). The last restriction basically because the output format is different (PE/COFF vs ELF). The object files between e.g. Win32 and WinCE on x86 are compatible and the different ELF based systems might be compatible if they run on the same platform (don't know that for sure though). But even if you'd have compatible object files you'd have the problem that e.g. the Linux one might contain different assumptions about structures and call different functions than the FreeBSD one (thus problems when linking or during runtime). Regards, Sven ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Re: Pascal and static executable
> Why does Pascal compiler generate static linked executable while C/++ compiler will generate dynamic executable ? It's really compiler dependent. There are Pascal compilers that generate dynamically linked executables by default and there are C/C++ compilers that generate static executables by default. > What are the benefits in this approach and what are the bad things with it > ? As stated by Jonas + from me: one bad thing about static linking, you can't have modular application at binary level, i.e. a couple of executables that share common codes residing in dynamically linked libraries. one good thing, static linking allows the linker to do dead code elimination (smartlinking in FPC term), so your executables contain only codes + datas that it really uses, thus reducing the size. -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Pascal-and-static-executable-tp4598551p4600397.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Re: Object Files
> Are object files platform dependent? No > Can you use object files created on Windows with a project compiled on > Linux? Only if they're cross compiled to target Linux > Something tells me they ARE platform independent since they have to be > linked in. Pardon me? That seems unrelated. Object files are basically executables with external symbols unresolved and no starting point, do you think executables platform independent? -- View this message in context: http://free-pascal-general.1045716.n5.nabble.com/Object-Files-tp4599906p4600367.html Sent from the Free Pascal - General mailing list archive at Nabble.com. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
[fpc-pascal] Object Files
Are object files platform dependent? Can you use object files created on Windows with a project compiled on Linux? Never used them before. Something tells me they ARE platform independent since they have to be linked in. -- Warm Regards, Lee ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Pascal and static executable
On 18 Jul 2011, at 10:03, ik wrote:
> Let's say that I write the following code:
>
> program say_hello;
>
> begin
> writeln('Hello');
> end.
>
> program say_helloworld;
>
> begin
> writeln('Hello World');
> end.
>
> They both have the same size and the same memory footprint.
> So what exactly is going on ?
Alignment/rounding of section sizes.
> Why does Pascal compiler generate static
> linked executable while C/++ compiler will generate dynamic executable ?
>
> What are the benefits in this approach and what are the bad things with it ?
With static linking, you can copy the program to other systems and it will
normally just work. With dynamic linking, the target systems needs a version of
the same dynamic library (or a compatible version for the program to run. The
advantage of dynamic linking is that shared libraries can be loaded in memory
just once, and then the same copy of the library can be used by all programs
that link to it (with copy-on-write for writable sections of the data, so that
programs won't influence each other when writing).
FPC's rtl interface is not very stable, so using a shared library approach
would probably cause lots of compatibility problems (or require the
installation of many different version of the FPC rtl shared library, with most
programs using a different version). The interface of libstdc++ changes less
often.
Jonas___
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[fpc-pascal] Pascal and static executable
Hello List,
I'm writing an article about modern (Object) Pascal, but there is one
subject that I do not fully understand (for the article that is :)) and I
wish to be prepared for it.
Let's say that I write the following code:
program say_hello;
begin
writeln('Hello');
end.
This code is not linked to any shared library and therefor consider to be
static linked. However if I write the following code:
program say_helloworld;
begin
writeln('Hello World');
end.
They both have the same size and the same memory footprint.
So what exactly is going on ? Why does Pascal compiler generate static
linked executable while C/++ compiler will generate dynamic executable ?
What are the benefits in this approach and what are the bad things with it ?
Thanks,
Ido
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