Re: C++ vs. glibc/Hurd/Mach headers

[Thomas Schwinge]

Hi!

On Sat, 26 Nov 2016 13:36:22 +0100, Samuel Thibault <samuel.thibault@gnu.org> 
wrote:
> Thomas Schwinge, on Fri 25 Nov 2016 12:46:33 +0100, wrote:
> > Additionally to the issues Samuel pointed
> > out in <https://www.sourceware.org/ml/libc-alpha/2007-08/msg00001.html>
> > (still unresolved),
> 
> ?
> 
> I can include hurd/signal.h fine from c++. The second part of my patch
> was applied

Right, hurd/signal.h's hurd_self_sigstate, _hurd_critical_section_lock,
and _hurd_critical_section_unlock have been fixed, but...

> and IIRC we made some changes to error_t.

... I don't see any such changes?

For GDB, the following is expected to work:

    $ echo -e '#include <errno.h>\n#include <mach.h>\n#include 
<hurd.h>\n#include <hurd/signal.h>\nvoid f(){ error_t err = 0; err = 
thread_get_state(0,0,0,0); err = HURD_MSGPORT_RPC(0,0,0,0); }' | g++ 
-D_GNU_SOURCE -x c++ - -S -o /dev/null -O2
    In file included from /usr/include/errno.h:35:0,
                     from <stdin>:1:
    /usr/include/hurd.h: In function ‘int __hurd_fail(error_t)’:
    /usr/include/hurd.h:60:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = EIEIO;
                 ^
    /usr/include/hurd.h:64:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = ENOMEM;
                 ^
    /usr/include/hurd.h:68:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = EINVAL;
                 ^
    <stdin>: In function ‘void f()’:
    <stdin>:5:25: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]
    <stdin>:5:50: error: invalid conversion from ‘kern_return_t {aka int}’ to 
‘error_t {aka __error_t_codes}’ [-fpermissive]
    In file included from /usr/include/hurd/userlink.h:27:0,
                     from /usr/include/hurd/port.h:25,
                     from /usr/include/hurd.h:41,
                     from <stdin>:3:
    <stdin>:5:67: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]
    <stdin>:5:67: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]
    <stdin>:5:67: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]

When changing the GDB source code to use kern_return_t (or int) instead
of error_t, I still see hurd.h:__hurd_fail and
hurd/signal.h:HURD_MSGPORT_RPC choke on their own error_t usage:

    $ echo -e '#include <errno.h>\n#include <mach.h>\n#include 
<hurd.h>\n#include <hurd/signal.h>\nvoid f(){ kern_return_t err = 0; err = 
thread_get_state(0,0,0,0); err = HURD_MSGPORT_RPC(0,0,0,0); }' | g++ 
-D_GNU_SOURCE -x c++ - -S -o /dev/null -O2
    In file included from /usr/include/errno.h:35:0,
                     from <stdin>:1:
    /usr/include/hurd.h: In function ‘int __hurd_fail(error_t)’:
    /usr/include/hurd.h:60:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = EIEIO;
                 ^
    /usr/include/hurd.h:64:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = ENOMEM;
                 ^
    /usr/include/hurd.h:68:13: error: invalid conversion from ‘int’ to ‘error_t 
{aka __error_t_codes}’ [-fpermissive]
           err = EINVAL;
                 ^
    In file included from /usr/include/hurd/userlink.h:27:0,
                     from /usr/include/hurd/port.h:25,
                     from /usr/include/hurd.h:41,
                     from <stdin>:3:
    <stdin>: In function ‘void f()’:
    <stdin>:5:73: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]
    <stdin>:5:73: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]
    <stdin>:5:73: error: invalid conversion from ‘int’ to ‘error_t {aka 
__error_t_codes}’ [-fpermissive]


Grüße
 Thomas