A fortran main program and a fortran shared library dlopen'ed from the main
program use the same unit number to report results to two different files
(explicitely opened in the main program and in the library, see example below)
With GCC 3.x when one links with libg2c.a to produce the shared library
(i.e.
g77 -shared -fPIC -Wl,-Bsymbolic -o libtest.so test.f /usr/lib64/libg2c.a
)
output goes to the two files as intended.
With gfortran 4.0.2 and also snapshot 4.1.0 20051022 the attempt to write
to the file in the shared library fails with
Fortran runtime error: End of record
In this case I have used
gfortran -fPIC -shared -Wl,-Bsymbolic -o libtest.so test.f
/usr/lib64/libgfortran.a
gcc -c testx.c
gfortran main.f testx.o -ldl
to produce the executable and the shared library.
When the shared library is built without libgfortran.a,
once unit 1 is opened in the shared library, all output goes
to this file, not the file connected to unit 1 in the main program.
I'm not sure if this is a bug or intended behavior.
c----------------------- test.f
subroutine test
open(1,file='junk_shared')
write(1,*) 'In subroutine test'
return
end
/*----------------- testx.c
#include <dlfcn.h>
#include <stdio.h>
typedef void (*MyFunc)();
void testx_() {
void *h; MyFunc func;
h = dlopen("./libtest.so",RTLD_LAZY);
if( !h ) {
printf("Failed to open libtest: %s\n",dlerror());
return;
}
func = (MyFunc) dlsym(h,"test_");
if( !func ) {
printf("Failed to resolve test: %s\n",dlerror());
return;
}
func();
}
c-------------- main.f
program io_test
open(1,file='junk_main')
write(1,*) 'In main program, calling testx'
call testx
write(1,*) 'Back in main program after call to testx: '
end
--
Summary: Fortran I/O to same unit number in main program and in a
shared library
Product: gcc
Version: 4.0.2
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: iwan at irs dot phy dot nrc dot ca
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24576
