Dear all,
I am facing an issue with passing a pointer to a subroutine. Here is a simplified version of my code:
program test_ptr
interface
subroutine sub(iptr)
dimension iptr(5)
end subroutine sub
end interface
save
integer, dimension(:), pointer :: iptr
allocate(iptr(5))
iptr = 0
call sub(iptr)
deallocate(iptr)
end
subroutine sub(iptr)
integer, dimension(:), pointer :: iptr
c dimension iptr(5)
end
If I declare iptr allocatable in the subroutine (commented line), everything goes fine. However I want iptr be a pointer in the subroutine, and in this case my code fails on a memory fault at the moment it enters the subroutine.
The attached code does not fail (must be too simple for that) but valgrind complains about invalid reads.
I have compiled with gfortran and passed through valgrind the same code, and there were no issues at all (except that gfortran insisted I add an interface block).
My compile/run instructions and output follow:
> ifort -g -O0 test_pointer.F; valgrind --leak-check=full --show-reachable=yes ./a.out ==18156== Memcheck, a memory error detector ==18156== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al. ==18156== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info ==18156== Command: ./a.out ==18156== ==18156== Invalid read of size 8 ==18156== at 0x403256: sub_ (test_pointer.F:23) ==18156== by 0x403095: MAIN__ (test_pointer.F:16) ==18156== by 0x402E7D: main (in /home/emakarov/FlowSimulator/test_pointer/a.out) ==18156== Address 0x5c1f120 is not stack'd, malloc'd or (recently) free'd ==18156== ==18156== Invalid read of size 8 ==18156== at 0x403259: sub_ (test_pointer.F:23) ==18156== by 0x403095: MAIN__ (test_pointer.F:16) ==18156== by 0x402E7D: main (in /home/emakarov/FlowSimulator/test_pointer/a.out) ==18156== Address 0x5c1f130 is not stack'd, malloc'd or (recently) free'd ==18156== ==18156== ==18156== HEAP SUMMARY: ==18156== in use at exit: 32 bytes in 1 blocks ==18156== total heap usage: 3 allocs, 2 frees, 68 bytes allocated ==18156== ==18156== 32 bytes in 1 blocks are still reachable in loss record 1 of 1 ==18156== at 0x4C26E77: calloc (vg_replace_malloc.c:593) ==18156== by 0x5A1C53F: _dlerror_run (in /lib64/libdl-2.11.2.so) ==18156== by 0x5A1C0A9: dlsym (in /lib64/libdl-2.11.2.so) ==18156== by 0x40D90E: for__aio_init (in /home/emakarov/FlowSimulator/test_pointer/a.out) ==18156== by 0x405C29: for_rtl_init_ (in /home/emakarov/FlowSimulator/test_pointer/a.out) ==18156== by 0x402E78: main (in /home/emakarov/FlowSimulator/test_pointer/a.out) ==18156== ==18156== LEAK SUMMARY: ==18156== definitely lost: 0 bytes in 0 blocks ==18156== indirectly lost: 0 bytes in 0 blocks ==18156== possibly lost: 0 bytes in 0 blocks ==18156== still reachable: 32 bytes in 1 blocks ==18156== suppressed: 0 bytes in 0 blocks ==18156== ==18156== For counts of detected and suppressed errors, rerun with: -v ==18156== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 2 from 2)
> gfortran -g -O0 test_pointer.F; valgrind --leak-check=full --show-reachable=yes ./a.out ==18171== Memcheck, a memory error detector ==18171== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al. ==18171== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info ==18171== Command: ./a.out ==18171== ==18171== ==18171== HEAP SUMMARY: ==18171== in use at exit: 0 bytes in 0 blocks ==18171== total heap usage: 22 allocs, 22 frees, 12,091 bytes allocated ==18171== ==18171== All heap blocks were freed -- no leaks are possible ==18171== ==18171== For counts of detected and suppressed errors, rerun with: -v ==18171== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)
I would appreciate any help with this issue.
Ekaterina.
