From 46a72f685cf96f655f0504ed98ebc22af7529013 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Sun, 16 Oct 2022 11:48:18 -0400
Subject: [PATCH] address portability issues to the flang LLVM Fortran 2018
 compiler

---
 unittest/fortran/test_fortran_extract_variable.f90 |  4 ++--
 unittest/fortran/test_fortran_gather_scatter.f90   | 13 +++++++------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/unittest/fortran/test_fortran_extract_variable.f90 b/unittest/fortran/test_fortran_extract_variable.f90
index c10e3eaa04..862cb894e5 100644
--- a/unittest/fortran/test_fortran_extract_variable.f90
+++ b/unittest/fortran/test_fortran_extract_variable.f90
@@ -60,7 +60,7 @@ CONTAINS
 
     INTERFACE
       FUNCTION lammps_malloc(size) BIND(C, name='malloc')
-        IMPORT :: c_ptr, c_size_t
+        USE, INTRINSIC :: ISO_C_BINDING, ONLY : c_ptr, c_size_t
         IMPLICIT NONE
         INTEGER(c_size_t), VALUE :: size
         TYPE(c_ptr) :: lammps_malloc
@@ -94,7 +94,7 @@ FUNCTION f_lammps_with_C_args(argc, argv) BIND(C)
 
   INTERFACE
     FUNCTION c_strlen(str) BIND(C,name='strlen')
-      IMPORT :: c_ptr, c_size_t
+      USE ISO_C_BINDING, ONLY: c_ptr, c_size_t
       IMPLICIT NONE
       TYPE(c_ptr), INTENT(IN), VALUE :: str
       INTEGER(c_size_t) :: c_strlen
diff --git a/unittest/fortran/test_fortran_gather_scatter.f90 b/unittest/fortran/test_fortran_gather_scatter.f90
index ec1880c908..d9bd27bba9 100644
--- a/unittest/fortran/test_fortran_gather_scatter.f90
+++ b/unittest/fortran/test_fortran_gather_scatter.f90
@@ -71,13 +71,13 @@ FUNCTION f_lammps_gather_atoms_concat_mask(i) BIND(C)
 
   CALL lmp%gather_atoms_concat('mask', 1_c_int, mask)
   CALL lmp%gather_atoms_concat('id', 1_c_int, tag)
+  f_lammps_gather_atoms_concat_mask = -1
   DO j = 1, SIZE(tag)
     IF (tag(j) == i) THEN
       f_lammps_gather_atoms_concat_mask = mask(j)
-      RETURN
+      EXIT
     END IF
   END DO
-  f_lammps_gather_atoms_concat_mask = -1
 END FUNCTION f_lammps_gather_atoms_concat_mask
 
 FUNCTION f_lammps_gather_atoms_concat_position(xyz, id) BIND(C)
@@ -93,6 +93,7 @@ FUNCTION f_lammps_gather_atoms_concat_position(xyz, id) BIND(C)
 
   CALL lmp%gather_atoms_concat('x', 3_c_int, positions)
   CALL lmp%gather_atoms_concat('id', 1_c_int, tag)
+  f_lammps_gather_atoms_concat_position = -1.0_c_double
   DO j = 1, SIZE(tag)
     IF (tag(j) == id) THEN
        f_lammps_gather_atoms_concat_position = positions((j-1)*3 + xyz)
@@ -112,13 +113,13 @@ FUNCTION f_lammps_gather_atoms_subset_mask(i) BIND(C)
   INTEGER(c_int), DIMENSION(*), PARAMETER :: tag = [3,2]
 
   CALL lmp%gather_atoms_subset('mask', 1_c_int, tag, mask)
+  f_lammps_gather_atoms_subset_mask = -1
   DO j = 1, SIZE(tag)
     IF (tag(j) == i) THEN
       f_lammps_gather_atoms_subset_mask = mask(j)
-      RETURN
+      EXIT
     END IF
   END DO
-  f_lammps_gather_atoms_subset_mask = -1
 END FUNCTION f_lammps_gather_atoms_subset_mask
 
 FUNCTION f_lammps_gather_atoms_subset_position(xyz,id) BIND(C)
@@ -133,13 +134,13 @@ FUNCTION f_lammps_gather_atoms_subset_position(xyz,id) BIND(C)
   INTEGER :: j
 
   CALL lmp%gather_atoms_subset('x', 3_c_int, tag, positions)
+  f_lammps_gather_atoms_subset_position = -1.0_c_double
   DO j = 1, SIZE(tag)
     IF (tag(j) == id) THEN
       f_lammps_gather_atoms_subset_position = positions((j-1)*3 + xyz)
-      RETURN
+      EXIT
     END IF
   END DO
-  f_lammps_gather_atoms_subset_position = -1.0D0
 END FUNCTION f_lammps_gather_atoms_subset_position
 
 SUBROUTINE f_lammps_scatter_atoms_masks() BIND(C)