https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100870
Bug ID: 100870
Summary: Constant expression for bind(C) name in interface body
not importable
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: ehlert at thch dot uni-bonn.de
Target Milestone: ---
Created attachment 50906
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50906&action=edit
Minimal reproducer
Following example fails to compile with GFortran 10.2.0. The example was
checked with Intel's and NAG's Fortran compiler, which both accept the usage of
constant expressions imported into an interface body as valid Fortran code.
>From the Fortran standard this usage is valid Fortran 2003.
Code example to trigger the bug (also in os.f90 attachment):
module m_os
use, intrinsic :: iso_c_binding
implicit none
character(len=*), parameter :: chdir_symbol = "chdir"
interface
function chdir(path) result(stat) bind(C, name=chdir_symbol)
import :: c_char, c_int, chdir_symbol
character(kind=c_char, len=1), intent(in) :: path(*)
integer(c_int) :: stat
end function chdir
end interface
end module m_os
Output showing GFortran rejecting this code with an error
❯ gfortran -v -save-temps -Wall -Wextra -fno-strict-aliasing -fwrapv -c os.f90
Using built-in specs.
COLLECT_GCC=gfortran
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --with-isl
--with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit
--enable-cet=auto --enable-checking=release --enable-clocale=gnu
--enable-default-pie --enable-default-ssp --enable-gnu-indirect-function
--enable-gnu-unique-object --enable-install-libiberty --enable-linker-build-id
--enable-lto --enable-multilib --enable-plugin --enable-shared
--enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-libunwind-exceptions --disable-werror
gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (GCC)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-Wextra' '-fno-strict-aliasing'
'-fwrapv' '-c' '-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/f951 os.f90 -quiet -dumpbase os.f90
-mtune=generic -march=x86-64 -auxbase os -Wall -Wextra -version
-fno-strict-aliasing -fwrapv -fintrinsic-modules-path
/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/finclude
-fpre-include=/usr/include/finclude/math-vector-fortran.h -o os.s
GNU Fortran (GCC) version 10.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 10.2.0, GMP version 6.2.1, MPFR version
4.1.0, MPC version 1.2.1, isl version isl-0.21-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU Fortran2008 (GCC) version 10.2.0 (x86_64-pc-linux-gnu)
compiled by GNU C version 10.2.0, GMP version 6.2.1, MPFR version
4.1.0, MPC version 1.2.1, isl version isl-0.21-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
os.f90:7:51:
7 | function chdir(path) result(stat) bind(C, name=chdir_symbol)
| 1
Error: Parameter ‘chdir_symbol’ at (1) has not been declared or is a variable,
which does not reduce to a constant expression
os.f90:8:13:
8 | import :: c_char, c_int, chdir_symbol
| 1
Error: IMPORT statement at (1) only permitted in an INTERFACE body
os.f90:9:21:
9 | character(kind=c_char, len=1), intent(in) :: path(*)
| 1
Error: Parameter ‘c_char’ at (1) has not been declared or is a variable, which
does not reduce to a constant expression
os.f90:10:14:
10 | integer(c_int) :: stat
| 1
Error: Parameter ‘c_int’ at (1) has not been declared or is a variable, which
does not reduce to a constant expression
os.f90:11:7:
11 | end function chdir
| 1
Error: Expecting END INTERFACE statement at (1)
