https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93308
Bug ID: 93308
Summary: bind(c) subroutine changes lower bound of array
argument in caller
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: r.j.hogan at reading dot ac.uk
Target Milestone: ---
Created attachment 47670
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47670&action=edit
Self contained source file that demonstrates the bug
When the attached program is compiled and run, the allocatable array has its
lbound changed from 1 to 0 when it returns from the bind(c) routine, while the
explicit-shape array does not. This can be seen from the output line:
After call: lbound(A) = 0 , A(1) = 2.00000000
Correct behaviour (the lbound is not changed) is found when the same code is
compiled using gfortran 8.3.0 or earlier, or using the Intel Fortran compiler.
Note that all versions of gfortran I have used issue the following warning,
whether or not their behaviour is correct:
Warning: Variable ‘v’ at (1) is a dummy argument of the BIND(C) procedure
‘routine_bindc’ but may not be C interoperable [-Wc-binding-type]
This bug is unfortunate because as far as I can see the other Fortran-2018
aspects of passing arrays to and from C/C++ work well.
Thanks, Robin Hogan.
$ gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.2.1-9ubuntu2'
--with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-9
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-bootstrap --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib
--with-target-system-zlib=auto --enable-multiarch --disable-werror
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none,hsa
--without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.2.1 20191008 (Ubuntu 9.2.1-9ubuntu2)
