Xref: utzoo comp.windows.x:29339 alt.toolkits.xview:62
Path: utzoo!utgpu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!apple!uokmax!munnari.oz.au!mel.dit.csiro.au!yarra!bksmel!paulf
From: paulf@bksmel.oz.au (Paul Fitchett)
Newsgroups: comp.windows.x,alt.toolkits.xview
Subject: Problem porting XView 2.0 to DG AviiON ( varargs )
Message-ID: <348@bksmel.oz.au>
Date: 7 Nov 90 22:05:48 GMT
Followup-To: comp.windows.x
Lines: 49

Hi,
I'm trying to port XView 2.0 to the DG AViiON and have run into trouble with
the Attr_avlist stuff.
Certain code in the distribution assumes that va_list is of a type that
can be cast to unsigned long. On a Sun this happens to be true, as va_list is
defined to be char *, however on a DG va_list is a structure:

typedef struct {
        int  __va_arg;          /* argument number */
        int *__va_stk;          /* start of args passed on stack */
        int *__va_reg;          /* start of args passed in regs */
} va_list;

There appears to be a way around this using attr_create() to make the
Attr_avlist from the va_list, however this requires that NON_PORTABLE be
undefined in the file attr.c. A consquence of this is that the function
attr_copy_valist() (which is declared extern in attr_impl.h) is required.
I cannot find the *.c file containing the definition of attr_copy_valist() at
all. In the file attr.c there is a comment that refers to a file
attr_portable.c, which is not present, perhaps this file is the one I need.

The problem occurs in certain files (such as cms_pblc.c) which have the
following construct:

Pkg_private Xv_opaque
cms_get_attr(cms_public, status, attr, args)
    Cms                 cms_public;
    int                 *status;
    Cms_attribute       attr;
    va_list             args;
{
    Cms_info            *cms = CMS_PRIVATE(cms_public);
    Xv_opaque           value;
    Attr_avlist         avlist = (Attr_avlist) args;		<---
    int                 cms_status = 0;

    switch (attr) {

The line marked with <--- is rejected by the compiler on the DG and should
perhaps be replaced by a call to attr_create() to make the avlist from the
args in a portable way.

If anyone can help me by sending the missing files, or by explaining how to
get around this problem, or indeed by correcting a misunderstanding I may
have about any of this, I would be very grateful.

Thanks,
Paul Fitchett
(paulf@bksmel.oz.au)