https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102727
Bug ID: 102727
Summary: Warning for guaranteed interoperable type kind
Product: gcc
Version: 11.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jahns at dkrz dot de
Target Milestone: ---
Created attachment 51594
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51594&action=edit
Source file to reproduce the unexpected interop warning.
Compiling a source like the following (also attached) gives a warning with
-Wc-binding-type active:
SUBROUTINE fwrap(another_int)
IMPLICIT NONE
INTEGER, INTENT(in) :: another_int
ENUM, BIND(c)
ENUMERATOR :: enu_a, enu_b
END ENUM
INTEGER, PARAMETER :: enu_type_kind = KIND(enu_a)
INTERFACE
SUBROUTINE wrapped_c(enu) BIND(C, name='wrapped_c')
IMPORT:: enu_type_kind
INTEGER(enu_type_kind), VALUE :: enu
END SUBROUTINE wrapped_c
END INTERFACE
IF (another_int < 0_enu_type_kind .OR. &
another_int > enu_b) &
CALL abort()
CALL wrapped_c(INT(another_int, enu_type_kind))
END SUBROUTINE fwrap
$ gfortran -c -o enum-warn.o -Wall -Wextra -Wconversion -Wstrict-overflow
enum-warn.f90
enum-warn.f90:9:28:
9 | SUBROUTINE wrapped_c(enu) BIND(C, name='wrapped_c')
| 1
Warning: Variable 'enu' at (1) is a dummy argument of the BIND(C) procedure
'wrapped_c' but may not be C interoperable
[https://gcc.gnu.org/onlinedocs/gfortran/Error-and-Warning-Options.html#index-Wc-binding-type-Wc-binding-type]
I also tried to change the interface block to
INTERFACE
SUBROUTINE wrapped_c(enu) BIND(C, name='wrapped_c')
IMPORT:: enu_a
INTEGER(KIND(enu_a)), VALUE :: enu
END SUBROUTINE wrapped_c
END INTERFACE
but that didn't seem to change anything.
This is on linux x86_64 with a compiler built with default spack configurations
applied. I can dig up more details if required.
The stackoverflow discussion leading to this report is at
<https://stackoverflow.com/questions/69546068>
