ifx: F_C_STRING does not accept non-default kind for ASIS argument

[Harald1]

Hello,

the following program in F2023 conforming but rejected by ifx 2025.0:

program p
  use iso_c_binding
  implicit none
  character(kind=c_char,len=*), parameter :: s = "abc"
  print *, f_c_string (s)
  print *, f_c_string (s,.false.)
  print *, f_c_string (s,.true.)
  print *, .false._1, .true._2,.false._4,.true._8
  print *, f_c_string (s,.false._1) ! rejected
  print *, f_c_string (s,.true._2)  ! rejected
  print *, f_c_string (s,.false._4) ! OK
  print *, f_c_string (s,.true._8)  ! rejected
end

 I find:

% ifx ifx_f_c_string.f90
ifx_f_c_string.f90(9): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.false._1) ! rejected
-----------^
ifx_f_c_string.f90(10): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.true._2)  ! rejected
-----------^
ifx_f_c_string.f90(12): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.true._8)  ! rejected
-----------^
compilation aborted for ifx_f_c_string.f90 (code 1)

 F2023:18.2.3.9 has:

ASIS (optional) shall be a logical scalar.

There is no restriction on ASIS being only of default kind.

Furthermore, the handling of ASIS as an optional argument should be such that the following code works:

program p
  use iso_c_binding
  implicit none
  character(kind=c_char,len=*), parameter :: s = "abc"
  call sub (.true.)
  call sub (.false.)
  call sub ()
contains
  subroutine sub (asis)
    logical, optional, intent(in) :: asis
    print *, f_c_string (s, asis)
  end
end

I get:

% ifx ifx_f_c_string2.f90 -g -traceback && ./a.out 
ifx: remark #10440: Note that use of a debug option without any optimization-level option will turnoff most compiler optimizations similar to use of '-O0'
 abc
 abc
forrtl: severe (174): SIGSEGV, segmentation fault occurred
Image              PC                Routine            Line        Source             
libpthread-2.31.s  00007F5C7B702910  Unknown               Unknown  Unknown
a.out              0000000000415342  Unknown               Unknown  Unknown
a.out              000000000040426A  sub                        11  ifx_f_c_string2.f90
a.out              00000000004041CE  p                           7  ifx_f_c_string2.f90
a.out              000000000040417D  Unknown               Unknown  Unknown
libc-2.31.so       00007F5C7B52324D  __libc_start_main     Unknown  Unknown
a.out              00000000004040AA  Unknown               Unknown  Unknown

Thanks,

Harald

[TobiasK]

@Harald1

thank you for reporting this. I escalated it to our development team.

[TobiasK]

@Harald1 the fix will be in the next release, 2025.2.

Best

Tobias

[Harald1]

It is not fixed here:

ifx -what ifx_f_c_string.f90
 Intel(R) Fortran 25.0-1485
ifx_f_c_string.f90(9): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.false._1) ! rejected
-----------^
ifx_f_c_string.f90(10): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.true._2)  ! rejected
-----------^
ifx_f_c_string.f90(12): error #6284: There is no matching specific function for this generic function reference.   [F_C_STRING]
  print *, f_c_string (s,.true._8)  ! rejected
-----------^
compilation aborted for ifx_f_c_string.f90 (code 1)