[Bug c/20951] New: bogus error passing &va_list to va_list*

[sebor at roguewave dot com]

The program below fails to compile with gcc on EM64T. I believe the program is
well-formed based on 7.15.1.1 of C99, Footnote 212 (I am aware that footnotes
are not normative).

The second program below uses va_copy to get around the compilation error in the
first case fails to compile with the -ansi option (I am aware of gcc-specific
__builtin_va_copy). Even if the program did compile the solution seems
unreasonably complicated.

Can you confirm whether you agree that this is a conformance bug or not and if
not explain why not?

$ cat t.cpp && g++ --version && g++ -c t.cpp
#include <stdarg.h>

void foo (int, va_list*);

void bar (int i, va_list va)
{
    foo (i, &va);
}
g++ (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-47)
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

t.cpp: In function `void bar(int, __va_list_tag*)':
t.cpp:7: cannot convert `__va_list_tag**' to `__va_list_tag (*)[1]' for 
   argument `2' to `void foo(int, __va_list_tag (*)[1])'


$ cat t.cpp && g++ --version && g++ -ansi t.cpp
#include <assert.h>
#include <stdarg.h>
#include <stdio.h>

int a [3];

int foo (int i, va_list *pva)
{
    a [i++] = va_arg (*pva, int);
    return i;
}

void bar (int i, va_list va)
{
    a [i++] = va_arg (va, int);

#ifdef va_copy
    va_list cpy;
    va_copy (cpy, va);
    va_end (va);
    i = foo (i, &cpy);
    va_copy (va, cpy);
    va_end (cpy);
#else
    i = foo (i, &va);
#endif

    a [i++] = va_arg (va, int);
}

void baz (int i, ...)
{
    va_list va;
    va_start (va, i);
    bar (i, va);
    va_end (va);
}

int main ()
{
    baz (0, 1, 2, 3);

    printf ("%d, %d, %d\n", a [0], a [1], a [2]);

    assert (1 == a [0]);
    assert (2 == a [1]);
    assert (3 == a [2]);
}
g++ (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-47)
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

t.cpp: In function `void bar(int, __va_list_tag*)':
t.cpp:25: cannot convert `__va_list_tag**' to `__va_list_tag (*)[1]' for 
   argument `2' to `int foo(int, __va_list_tag (*)[1])'

-- 
           Summary: bogus error passing &va_list to va_list*
           Product: gcc
           Version: 3.2.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sebor at roguewave dot com
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: x86_64-redhat-linux
  GCC host triplet: x86_64-redhat-linux
GCC target triplet: x86_64-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20951