On Thu, 25 May 2006, Dominique Leducq wrote:
On Wed, 24 May 2006 15:40:27 +0200
Dominique Leducq <[EMAIL PROTECTED]> wrote:
On Wed, 24 May 2006 11:49:03 +0200 (CEST)
Michael Van Canneyt <[EMAIL PROTECTED]> wrote:
On Wed, 24 May 2006, Dominique Leducq wrote:
Hi again,
I still don't succeed in linking Free Pascal compiled code with a C program.
When linking with the shared library built by fpc, I have problems with
undefined symbols, which are defined in the loaders.
$ gcc -o test_shared test2.o -L. -lsoTest3
./libsoTest3.so: undefined reference to `__stkptr'
./libsoTest3.so: undefined reference to `_haltproc'
./libsoTest3.so: undefined reference to `operatingsystem_parameter_argc'
./libsoTest3.so: undefined reference to `operatingsystem_parameter_argv'
collect2: ld returned 1 exit status
When linking in the loader prt0.o too, there are symbol conflicts with
/usr/lib/crt1.o (_start, __data_start) if I call ld through gcc.
$ gcc -o test_shared test2.o prt0.o -L. -lsoTest3
prt0.o: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/lib/gcc/x86_64-linux-gnu/4.0.3/../../../../lib64/crt1.o:../sysdeps/x86_64/elf/start.S:65:
first defined here
prt0.o: In function `data_start':
(.data+0x0): multiple definition of `__data_start'
/usr/lib/gcc/x86_64-linux-gnu/4.0.3/../../../../lib64/crt1.o:(.data+0x0): first
defined here
collect2: ld returned 1 exit status
Exactly the same happens when linking statically.
If I call ld directly, linking succeeds, but the main() of the C program never
gets called...
However, according to the FPC Programmer's Guide, "using a pascal library from a C
program" (12.4) seems to be supported...
Do I miss something ?
That statement means that you can create a separate library,
which can be called from a C program.
That is actually what I want to do. How can I achieve this ? I followed the
steps in the Programmer Guide, to no avail.
OK, I've done it with this little trick :
$ gcc -c test3.c
$ gcc -o test3 test3.o dummy.o -L. -lsoTest5
with the source of dummy.c:
#define NULL (void *)0
long operatingsystem_parameter_argc = 0;
char **operatingsystem_parameter_argv = NULL;
char **operatingsystem_parameter_envp = NULL;
void *__stkptr = NULL;
void _haltproc(long e)
{
return;
}
When calling a library function that do no IO (only arithmetics on the
parameters), it works.
When doing simple IO (writeLn), it doesn't: I see calls to handleerror_frame,
get_frame, get_caller_frame, get_caller_addr, break_error... when debugging,
following calls to write_text_pchar_as_array and IOcheck
Add a call to FPC_INITIALIZEUNITS before calling any FPC routines, and
it should work fine.
Michael.
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