https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108961
Bug ID: 108961
Summary: Segfault when associating to pointer from C_F_POINTER
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jeffrey.p.hill at nasa dot gov
Target Milestone: ---
Created attachment 54551
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54551&action=edit
Full example of failing test
In support of exposing a Fortran library via a C API, I am trying to implement
C_F_STRPOINTER from the upcoming F202X standard in F2008:
https://j3-fortran.org/doc/year/19/19-197r3.txt
A sample implementation was provided in an earlier paper, as well as on the
Intel forums:
https://j3-fortran.org/doc/year/18/18-258r2.txt
https://community.intel.com/t5/Intel-Fortran-Compiler/New-Interoperability-Fortran-to-C-String-case/m-p/1144681/highlight/true#M138173
Example usage is provided in this paper:
https://j3-fortran.org/doc/year/21/21-107.txt
Attachment #1 is a full example that implements and exercises c_f_strpointer
per the above references. This works in ifort and nvfortran, but segfaults in
all versions of gfortran I tested (4.8 => 11). Tests were done under Ubuntu and
RH7. The problematic line is Line 37, when trying to associate the
deferred-length output pointer with the defined-length pointer returned by
c_f_pointer:
call C_F_POINTER(CSTRPTR, p)
FSTRPTR => p
Attachment #2 in a minimal example that just focuses on the C_F_POINTER/pointer
associate operations. I find the error only happens when the pointer
to-be-associated is in a separate module with deferred length.
Fall back is to simply copy the contents of the character array pointer into a
character string, but I was hoping to get this approach working, which is
zero-copy/zero-allocation.
Thanks!
