[Bug c/17881] New: Incomplete type warning is issued even for prototypes

[Bug c/17881] New: Incomplete type warning is issued even for prototypes

[jakub at gcc dot gnu dot org]

struct S;
struct foo { void (*bar) (struct S); };
void baz (struct S);

struct S { int i; };

void baz (struct S s)
{
  (void) s.i;
}

warns about the incomplete type in prototype and function pointer, although
the size of the object is not needed in those cases.

-- 
           Summary: Incomplete type warning is issued even for prototypes
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c++/17881] Incomplete type warning is issued even for prototypes

[bangerth at dealii dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |c++


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c/17881] Incomplete type warning is issued even for prototypes

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-07 13:22 -------
The code is C.... ("void (*bar) (struct S);" is a pointer to function).

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |c


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c/17881] Incomplete type warning is issued even for prototypes

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-07 16:29 -------
Confirmed but I really want a C person to comment here.  The C++ front-end does not warn about this.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |diagnostic
      Known to fail|                            |3.0.4 3.2.3 3.3.3
   Last reconfirmed|0000-00-00 00:00:00         |2004-10-07 16:29:33
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c/17881] Incomplete type warning is issued even for prototypes

[jsm at polyomino dot org dot uk]

------- Additional Comments From jsm at polyomino dot org dot uk  2004-10-07 19:44 -------
Subject: Re:  New: Incomplete type warning is issued even for
 prototypes

On Thu, 7 Oct 2004, jakub at gcc dot gnu dot org wrote:

> struct S;
> struct foo { void (*bar) (struct S); };
> void baz (struct S);
> 
> struct S { int i; };
> 
> void baz (struct S s)
> {
>   (void) s.i;
> }
> 
> warns about the incomplete type in prototype and function pointer, although
> the size of the object is not needed in those cases.

Although this is certainly a deliberate warning - and a warning, not a 
pedwarn - the comment justifying it

      /* If the arg types are incomplete in a declaration, they must
         include undefined tags.  These tags can never be defined in
         the scope of the declaration, so the types can never be
         completed, and no call can be compiled successfully.  */

is entirely wrong.  The case of tags defined at function prototype scope 
already gets its own warning.  Probably the only case for which this 
separate warning is appropriate is for parameters declared with void type 
(where a function with such parameter types can never be defined, only 
declared).



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c/17881] Incomplete type warning is issued even for prototypes

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-10-10 19:20 -------
Subject: Bug 17881

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	jsm28@gcc.gnu.org	2004-10-10 19:20:35

Modified files:
	gcc            : ChangeLog c-decl.c 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/gcc.dg: parm-incomplete-1.c 

Log message:
	PR c/17881
	* c-decl.c (grokparms): Don't warn for parameters of incomplete
	type in declarations that are not definitions except for the case
	of parameters of void type.
	
	testsuite:
	* parm-incomplete-1.c: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.5826&r2=2.5827
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-decl.c.diff?cvsroot=gcc&r1=1.598&r2=1.599
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.4428&r2=1.4429
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/parm-incomplete-1.c.diff?cvsroot=gcc&r1=NONE&r2=1.1



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881

[Bug c/17881] Incomplete type warning is issued even for prototypes

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-10 19:24 -------
Fixed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17881