initial commit

Makefile

+NVHPC_ROOT=/sw/hpcx/hpcx-v2.21-gcc-doca_ofed-redhat8-cuda12-x86_64/hpcx_nvhpc-24.11_mt
+FC=${NVHPC_ROOT}/bin/mpifort
+CC=${NVHPC_ROOT}/bin/mpicc
+FFLAGS=-g -O0 -cuda -acc=gpu,verystrict
+CFLAGS=-g -O0 -fPIC -cuda
+
+all: main plugin.so
+
+main: main.F90
+	${FC} ${FFLAGS} $< -o $@
+
+plugin.so: plugin.c
+	${CC} ${CFLAGS} $< -shared -o $@

README.md

+The segmentation fault only occurs on GPU nodes.
+
+E.g.:
+```
+salloc -p gpu --exclusive
+---
+make
+./main
+```

main.F90

+PROGRAM main
+
+  USE ISO_C_BINDING
+
+  INTERFACE
+    FUNCTION dlopen(filename,mode) BIND(c,name="dlopen")
+      ! void *dlopen(const char *filename, int mode);
+      USE ISO_C_BINDING
+      TYPE(c_ptr) :: dlopen
+      TYPE(c_ptr), VALUE, INTENT(in) :: filename
+      INTEGER(c_int), VALUE :: mode
+    END FUNCTION dlopen
+
+    FUNCTION dlclose(handle) BIND(c,name="dlclose")
+      ! int dlclose(void *handle);
+      USE ISO_C_BINDING
+      INTEGER(c_int) :: dlclose
+      TYPE(c_ptr), VALUE :: handle
+    END FUNCTION dlclose
+
+    FUNCTION DLError() RESULT(error) BIND(C,NAME="dlerror")
+      ! char *dlerror(void);
+      USE ISO_C_BINDING
+      TYPE(C_PTR) :: error
+    END FUNCTION DLError
+  END INTERFACE
+
+
+  TYPE(C_PTR) :: dlhandle
+  INTEGER(C_INT) :: dlclose_result
+  INTEGER(C_INT), PARAMETER :: RTLD_NOW = 2
+  CHARACTER(LEN=:), ALLOCATABLE, TARGET :: so_name
+  INTEGER :: ierr
+
+  so_name = "./plugin.so" // C_NULL_CHAR
+
+  WRITE (0,*) "Moin!"
+
+  dlhandle = dlopen(C_LOC(so_name), RTLD_NOW)
+  IF(.NOT. C_ASSOCIATED(dlhandle)) THEN
+    WRITE (0,*) convert_c_string_cptr(dlerror())
+    STOP 66
+  ENDIF
+
+  dlclose_result = dlclose(dlhandle)
+  IF(dlclose_result /= 0) THEN
+    WRITE (0,*) convert_c_string_cptr(dlerror())
+    STOP 67
+  ENDIF
+
+CONTAINS
+
+    !> Convert c-style character array into Fortran string.
+  !
+  FUNCTION convert_c_string_cptr( cptr ) RESULT (string)
+
+    USE, intrinsic :: iso_c_binding, only: c_ptr, c_char, &
+         c_f_pointer,c_size_t
+
+    TYPE(c_ptr), intent(in) :: cptr
+    CHARACTER(len=:), allocatable :: string
+    CHARACTER(kind=c_char), dimension(:), pointer :: chars
+    INTEGER(kind=c_size_t) :: strlen
+
+    INTERFACE
+      FUNCTION c_strlen(str_ptr) BIND ( C, name = "strlen" ) RESULT(len)
+        USE, INTRINSIC :: iso_c_binding
+        TYPE(c_ptr), VALUE      :: str_ptr
+        INTEGER(kind=c_size_t)  :: len
+      END FUNCTION c_strlen
+    END INTERFACE
+
+    strlen = c_strlen(cptr)
+    CALL c_f_pointer(cptr, chars, [ strlen ])
+    string = convert_c_string_arr(chars)
+  END FUNCTION convert_c_string_cptr
+
+  FUNCTION convert_c_string_arr( arr ) RESULT (string)
+    CHARACTER(kind=C_CHAR), INTENT(IN) :: arr(:)
+    CHARACTER(len=:), ALLOCATABLE :: string
+    INTEGER :: i, strlen
+
+    DO strlen=1,SIZE(arr)
+      IF (arr(strlen) .EQ. c_null_char) EXIT
+    END DO
+
+    ALLOCATE(CHARACTER(len=strlen-1) :: string)
+    DO i=1,strlen-1
+      string(i:i) = arr(i)
+    END DO
+  END FUNCTION convert_c_string_arr
+
+END PROGRAM main

plugin.c

+#include <stdio.h>
+
+void foo(){
+  printf("FOO");
+}