| Summary: | [Fortran 2008] Non-variable pointer expression as actual argument to INTENT(OUT) non-pointer dummy | ||
|---|---|---|---|
| Product: | gcc | Reporter: | Tobias Burnus <burnus> |
| Component: | fortran | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | Keywords: | rejects-valid |
| Priority: | P3 | ||
| Version: | 4.6.0 | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | ||
| Bug Depends on: | |||
| Bug Blocks: | 39627 | ||
|
Description
Tobias Burnus
2010-10-20 16:43:44 UTC
Forgot to add: In the current ISO Fortran standard (Fortran 2008), one finds: "If a nonpointer dummy argument without the VALUE attribute corresponds to a pointer actual argument that is pointer associated with a target, the dummy argument becomes argument associated with that target." "The INTENT (INOUT) attribute for a nonpointer dummy argument specifies that any actual argument that corresponds to the dummy argument shall be definable." "definable -- capable of definition and permitted to become defined" Thus, it boils down to the questions whether the target (to which the pointer is pointer associated) is definable. I think that is usually the case, which makes the example valid. * * * Note, however, that Richard Maine disagrees - he thinks that it is invalid Fortran 2003, while it might be valid Fortran 2008. I cannot see an essential difference between the F2003 and F2008 wording, but there might be. (See thread and see interpretation request F95/0074 in http://j3-fortran.org/doc/standing/links/022.txt . Using a pointer function as LHS of an assignment is tracked by F2008's PR 40054.) After carefully reading the interpretation request, http://www.j3-fortran.org/doc/year/08/08-172.txt, I think the reason that it is invalid in Fortran 95/2003 is that only variables are definable and as "f()" is not a variable, it is invalid. Fortran 2008 has (cf. PR 40054): R602 variable is designator or expr C602 (R602) expr shall be a reference to a function that has a pointer result." Which makes the program valid. Untested patch:
diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 5711634..ef516a4 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -4316,7 +4316,18 @@ gfc_check_vardef_context (gfc_expr* e, bool pointer, const char* context)
symbol_attribute attr;
gfc_ref* ref;
- if (e->expr_type != EXPR_VARIABLE)
+ if (!pointer && e->expr_type == EXPR_FUNCTION
+ && e->symtree->n.sym->result->attr.pointer)
+ {
+ if (!(gfc_option.allow_std & GFC_STD_F2008))
+ {
+ if (context)
+ gfc_error ("Fortran 2008: Pointer functions in variable definition"
+ " context (%s) at %L", context, &e->where);
+ return FAILURE;
+ }
+ }
+ else if (e->expr_type != EXPR_VARIABLE)
{
if (context)
gfc_error ("Non-variable expression in variable definition context (%s)"
Author: burnus Date: Thu Oct 21 06:15:30 2010 New Revision: 165749 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=165749 Log: 2010-10-21 Tobias Burnus <burnus@net-b.de> PR fortran/46100 * expr.c (gfc_check_vardef_context): Treat pointer functions as variables. 2010-10-21 Tobias Burnus <burnus@net-b.de> PR fortran/46100 * gfortran.dg/ptr-func-1.f90: New. * gfortran.dg/ptr-func-2.f90: New. Added: trunk/gcc/testsuite/gfortran.dg/ptr-func-1.f90 trunk/gcc/testsuite/gfortran.dg/ptr-func-2.f90 Modified: trunk/gcc/fortran/ChangeLog trunk/gcc/fortran/expr.c trunk/gcc/testsuite/ChangeLog FIXED on the trunk (4.6). |