https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92123
--- Comment #6 from Tobias Burnus <burnus at gcc dot gnu.org> --- Some side remarks: (In reply to Jakub Jelinek from comment #5) > The type used on the C side is: This type is described in the Fortran standard; for Fortran 2018, it is described in "18.5.3 The CFI_cdesc_t structure type" on page 481, cf. https://j3-fortran.org/doc/year/18/18-007r1.pdf That's defined on the gfortran side in libgfortran/ISO_Fortran_binding.h > typedef struct CFI_cdesc_t > { > void *base_addr; > size_t elem_len; … > where void * and size_t are 64-bit on LP64 and 32-bit on ILP32, > CFI_rank_t/CFI_attribute_t are 8-bit and CFI_type_t is 16-bit, while for > integer(c_int), allocatable, intent(out) :: dat(..) … > seems to assume dat type is a structure containing pointer sized data, > array index offset, and dtype, which has size_t elem_len, int version, 8-bit > rank, type and 16-bit attribute, so the Fortran FE assumption is there is > extra 64-bit (or 32-bit) offset and type/attribute are swapped and have > different types. The conversion between gfortran's internal array descriptor and the one use with C binding ("CFI_") is done in libgfortran/runtime/ISO_Fortran_binding.c via cfi_desc_to_gfc_desc and gfc_desc_to_cfi_desc; this function is called from the Fortran side. (When calling a bind(C) function or for implementing in Fortran a bind(C) function.) The C side calls CFI_establish for a likewise purpose (same file).
