bug#18508: Incomplete type pollfd

bug#18508: Incomplete type pollfd

[Andreas Enge]

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Hello,

guile-2.0.11 fails to build on Redhat 6.5 with the following error message:

  CC       libguile_2.0_la-fports.lo
fports.c: In function 'fport_input_waiting':
fports.c:612: error: variable 'pollfd' has initializer but incomplete type
fports.c:612: warning: excess elements in struct initializer
fports.c:612: warning: (near initialization for 'pollfd')
fports.c:612: error: 'POLLIN' undeclared (first use in this function)
fports.c:612: error: (Each undeclared identifier is reported only once
fports.c:612: error: for each function it appears in.)
fports.c:612: warning: excess elements in struct initializer
fports.c:612: warning: (near initialization for 'pollfd')
fports.c:612: warning: excess elements in struct initializer
fports.c:612: warning: (near initialization for 'pollfd')
fports.c:612: error: storage size of 'pollfd' isn't known
fports.c:614: warning: implicit declaration of function 'poll'
fports.c:612: warning: unused variable 'pollfd'
make[3]: *** [libguile_2.0_la-fports.lo] Error 1
make[3]: Leaving directory `/home/enge/lib-intel/guile-2.0.11/libguile'

Versions of software used:
gcc 4.4.7
libffi 3.0.5
libunistring 0.9.3
libgc 7.1
ltdl 2.2.6
gmp 4.3.1
pkg-config 0.23

I am attaching the config.log.

Andreas


[-- Attachment #2: config.log.xz --]
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bug#18507: Incomplete type pollfd

[Andreas Enge]

On Fri, Sep 19, 2014 at 12:16:15PM +0200, Andreas Enge wrote:
> gcc 4.4.7

It seems to be a problem with the gcc version; with gcc-4.8.3, I get past
this point. So maybe this bug report can be safely ignored.

Andreas

bug#18508: Incomplete type pollfd

[Ludovic Courtès]

Andreas Enge <andreas@enge.fr> skribis:

> guile-2.0.11 fails to build on Redhat 6.5 with the following error message:
>
>   CC       libguile_2.0_la-fports.lo
> fports.c: In function 'fport_input_waiting':
> fports.c:612: error: variable 'pollfd' has initializer but incomplete type
> fports.c:612: warning: excess elements in struct initializer
> fports.c:612: warning: (near initialization for 'pollfd')
> fports.c:612: error: 'POLLIN' undeclared (first use in this function)
> fports.c:612: error: (Each undeclared identifier is reported only once
> fports.c:612: error: for each function it appears in.)
> fports.c:612: warning: excess elements in struct initializer
> fports.c:612: warning: (near initialization for 'pollfd')
> fports.c:612: warning: excess elements in struct initializer
> fports.c:612: warning: (near initialization for 'pollfd')
> fports.c:612: error: storage size of 'pollfd' isn't known
> fports.c:614: warning: implicit declaration of function 'poll'
> fports.c:612: warning: unused variable 'pollfd'
> make[3]: *** [libguile_2.0_la-fports.lo] Error 1
> make[3]: Leaving directory `/home/enge/lib-intel/guile-2.0.11/libguile'
>
> Versions of software used:
> gcc 4.4.7

What libc version is this?

It would have been great, if this is still possible, to post lib/poll.h.
Normally that file uses #include_next to get libc’s <poll.h>, but maybe
that mechanism somehow fails with old GCC versions.

Ludo’.

bug#18508: Incomplete type pollfd

[Andreas Enge]

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On Mon, Sep 22, 2014 at 10:43:27AM +0200, Ludovic Courtès wrote:
> What libc version is this?

The package is glibc-2.12-1.107.el6_4.5.x86_64.

> It would have been great, if this is still possible, to post lib/poll.h.
> Normally that file uses #include_next to get libc’s <poll.h>, but maybe
> that mechanism somehow fails with old GCC versions.

I just retried the compilation, and poll.h is attached. It contains
#if 1
# include_next <poll.h>
#endif

There is a /usr/include/poll.h, which contains the one line
#include <sys/poll.h>
This in turn does an
#include <bits/poll.h>
which has a line
#define POLLIN          0x001           /* There is data to read.  */

I tried to replace the # include_next in lib/poll.h by a simple #include,
but that leads to
../lib/poll.h:31:18: error: #include nested too deeply

Andreas


[-- Attachment #2: poll.h --]
[-- Type: text/plain, Size: 15821 bytes --]

/* DO NOT EDIT! GENERATED AUTOMATICALLY! */
/* Header for poll(2) emulation
   Contributed by Paolo Bonzini.

   Copyright 2001-2003, 2007, 2009-2014 Free Software Foundation, Inc.

   This file is part of gnulib.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License along
   with this program; if not, see <http://www.gnu.org/licenses/>.  */

#ifndef _GL_POLL_H

#if __GNUC__ >= 3
#pragma GCC system_header
#endif


/* The include_next requires a split double-inclusion guard.  */
#if 1
# include_next <poll.h>
#endif

#ifndef _GL_POLL_H
#define _GL_POLL_H


/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
#ifndef _GL_CXXDEFS_H
#define _GL_CXXDEFS_H

/* The three most frequent use cases of these macros are:

   * For providing a substitute for a function that is missing on some
     platforms, but is declared and works fine on the platforms on which
     it exists:

       #if @GNULIB_FOO@
       # if !@HAVE_FOO@
       _GL_FUNCDECL_SYS (foo, ...);
       # endif
       _GL_CXXALIAS_SYS (foo, ...);
       _GL_CXXALIASWARN (foo);
       #elif defined GNULIB_POSIXCHECK
       ...
       #endif

   * For providing a replacement for a function that exists on all platforms,
     but is broken/insufficient and needs to be replaced on some platforms:

       #if @GNULIB_FOO@
       # if @REPLACE_FOO@
       #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
       #   undef foo
       #   define foo rpl_foo
       #  endif
       _GL_FUNCDECL_RPL (foo, ...);
       _GL_CXXALIAS_RPL (foo, ...);
       # else
       _GL_CXXALIAS_SYS (foo, ...);
       # endif
       _GL_CXXALIASWARN (foo);
       #elif defined GNULIB_POSIXCHECK
       ...
       #endif

   * For providing a replacement for a function that exists on some platforms
     but is broken/insufficient and needs to be replaced on some of them and
     is additionally either missing or undeclared on some other platforms:

       #if @GNULIB_FOO@
       # if @REPLACE_FOO@
       #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
       #   undef foo
       #   define foo rpl_foo
       #  endif
       _GL_FUNCDECL_RPL (foo, ...);
       _GL_CXXALIAS_RPL (foo, ...);
       # else
       #  if !@HAVE_FOO@   or   if !@HAVE_DECL_FOO@
       _GL_FUNCDECL_SYS (foo, ...);
       #  endif
       _GL_CXXALIAS_SYS (foo, ...);
       # endif
       _GL_CXXALIASWARN (foo);
       #elif defined GNULIB_POSIXCHECK
       ...
       #endif
*/

/* _GL_EXTERN_C declaration;
   performs the declaration with C linkage.  */
#if defined __cplusplus
# define _GL_EXTERN_C extern "C"
#else
# define _GL_EXTERN_C extern
#endif

/* _GL_FUNCDECL_RPL (func, rettype, parameters_and_attributes);
   declares a replacement function, named rpl_func, with the given prototype,
   consisting of return type, parameters, and attributes.
   Example:
     _GL_FUNCDECL_RPL (open, int, (const char *filename, int flags, ...)
                                  _GL_ARG_NONNULL ((1)));
 */
#define _GL_FUNCDECL_RPL(func,rettype,parameters_and_attributes) \
  _GL_FUNCDECL_RPL_1 (rpl_##func, rettype, parameters_and_attributes)
#define _GL_FUNCDECL_RPL_1(rpl_func,rettype,parameters_and_attributes) \
  _GL_EXTERN_C rettype rpl_func parameters_and_attributes

/* _GL_FUNCDECL_SYS (func, rettype, parameters_and_attributes);
   declares the system function, named func, with the given prototype,
   consisting of return type, parameters, and attributes.
   Example:
     _GL_FUNCDECL_SYS (open, int, (const char *filename, int flags, ...)
                                  _GL_ARG_NONNULL ((1)));
 */
#define _GL_FUNCDECL_SYS(func,rettype,parameters_and_attributes) \
  _GL_EXTERN_C rettype func parameters_and_attributes

/* _GL_CXXALIAS_RPL (func, rettype, parameters);
   declares a C++ alias called GNULIB_NAMESPACE::func
   that redirects to rpl_func, if GNULIB_NAMESPACE is defined.
   Example:
     _GL_CXXALIAS_RPL (open, int, (const char *filename, int flags, ...));
 */
#define _GL_CXXALIAS_RPL(func,rettype,parameters) \
  _GL_CXXALIAS_RPL_1 (func, rpl_##func, rettype, parameters)
#if defined __cplusplus && defined GNULIB_NAMESPACE
# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
    namespace GNULIB_NAMESPACE                                \
    {                                                         \
      rettype (*const func) parameters = ::rpl_func;          \
    }                                                         \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#else
# define _GL_CXXALIAS_RPL_1(func,rpl_func,rettype,parameters) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIAS_RPL_CAST_1 (func, rpl_func, rettype, parameters);
   is like  _GL_CXXALIAS_RPL_1 (func, rpl_func, rettype, parameters);
   except that the C function rpl_func may have a slightly different
   declaration.  A cast is used to silence the "invalid conversion" error
   that would otherwise occur.  */
#if defined __cplusplus && defined GNULIB_NAMESPACE
# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
    namespace GNULIB_NAMESPACE                                     \
    {                                                              \
      rettype (*const func) parameters =                           \
        reinterpret_cast<rettype(*)parameters>(::rpl_func);        \
    }                                                              \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#else
# define _GL_CXXALIAS_RPL_CAST_1(func,rpl_func,rettype,parameters) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIAS_SYS (func, rettype, parameters);
   declares a C++ alias called GNULIB_NAMESPACE::func
   that redirects to the system provided function func, if GNULIB_NAMESPACE
   is defined.
   Example:
     _GL_CXXALIAS_SYS (open, int, (const char *filename, int flags, ...));
 */
#if defined __cplusplus && defined GNULIB_NAMESPACE
  /* If we were to write
       rettype (*const func) parameters = ::func;
     like above in _GL_CXXALIAS_RPL_1, the compiler could optimize calls
     better (remove an indirection through a 'static' pointer variable),
     but then the _GL_CXXALIASWARN macro below would cause a warning not only
     for uses of ::func but also for uses of GNULIB_NAMESPACE::func.  */
# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
    namespace GNULIB_NAMESPACE                     \
    {                                              \
      static rettype (*func) parameters = ::func;  \
    }                                              \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#else
# define _GL_CXXALIAS_SYS(func,rettype,parameters) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIAS_SYS_CAST (func, rettype, parameters);
   is like  _GL_CXXALIAS_SYS (func, rettype, parameters);
   except that the C function func may have a slightly different declaration.
   A cast is used to silence the "invalid conversion" error that would
   otherwise occur.  */
#if defined __cplusplus && defined GNULIB_NAMESPACE
# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
    namespace GNULIB_NAMESPACE                          \
    {                                                   \
      static rettype (*func) parameters =               \
        reinterpret_cast<rettype(*)parameters>(::func); \
    }                                                   \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#else
# define _GL_CXXALIAS_SYS_CAST(func,rettype,parameters) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIAS_SYS_CAST2 (func, rettype, parameters, rettype2, parameters2);
   is like  _GL_CXXALIAS_SYS (func, rettype, parameters);
   except that the C function is picked among a set of overloaded functions,
   namely the one with rettype2 and parameters2.  Two consecutive casts
   are used to silence the "cannot find a match" and "invalid conversion"
   errors that would otherwise occur.  */
#if defined __cplusplus && defined GNULIB_NAMESPACE
  /* The outer cast must be a reinterpret_cast.
     The inner cast: When the function is defined as a set of overloaded
     functions, it works as a static_cast<>, choosing the designated variant.
     When the function is defined as a single variant, it works as a
     reinterpret_cast<>. The parenthesized cast syntax works both ways.  */
# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
    namespace GNULIB_NAMESPACE                                                \
    {                                                                         \
      static rettype (*func) parameters =                                     \
        reinterpret_cast<rettype(*)parameters>(                               \
          (rettype2(*)parameters2)(::func));                                  \
    }                                                                         \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#else
# define _GL_CXXALIAS_SYS_CAST2(func,rettype,parameters,rettype2,parameters2) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIASWARN (func);
   causes a warning to be emitted when ::func is used but not when
   GNULIB_NAMESPACE::func is used.  func must be defined without overloaded
   variants.  */
#if defined __cplusplus && defined GNULIB_NAMESPACE
# define _GL_CXXALIASWARN(func) \
   _GL_CXXALIASWARN_1 (func, GNULIB_NAMESPACE)
# define _GL_CXXALIASWARN_1(func,namespace) \
   _GL_CXXALIASWARN_2 (func, namespace)
/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
   we enable the warning only when not optimizing.  */
# if !__OPTIMIZE__
#  define _GL_CXXALIASWARN_2(func,namespace) \
    _GL_WARN_ON_USE (func, \
                     "The symbol ::" #func " refers to the system function. " \
                     "Use " #namespace "::" #func " instead.")
# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
#  define _GL_CXXALIASWARN_2(func,namespace) \
     extern __typeof__ (func) func
# else
#  define _GL_CXXALIASWARN_2(func,namespace) \
     _GL_EXTERN_C int _gl_cxxalias_dummy
# endif
#else
# define _GL_CXXALIASWARN(func) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

/* _GL_CXXALIASWARN1 (func, rettype, parameters_and_attributes);
   causes a warning to be emitted when the given overloaded variant of ::func
   is used but not when GNULIB_NAMESPACE::func is used.  */
#if defined __cplusplus && defined GNULIB_NAMESPACE
# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
   _GL_CXXALIASWARN1_1 (func, rettype, parameters_and_attributes, \
                        GNULIB_NAMESPACE)
# define _GL_CXXALIASWARN1_1(func,rettype,parameters_and_attributes,namespace) \
   _GL_CXXALIASWARN1_2 (func, rettype, parameters_and_attributes, namespace)
/* To work around GCC bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43881>,
   we enable the warning only when not optimizing.  */
# if !__OPTIMIZE__
#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
    _GL_WARN_ON_USE_CXX (func, rettype, parameters_and_attributes, \
                         "The symbol ::" #func " refers to the system function. " \
                         "Use " #namespace "::" #func " instead.")
# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
     extern __typeof__ (func) func
# else
#  define _GL_CXXALIASWARN1_2(func,rettype,parameters_and_attributes,namespace) \
     _GL_EXTERN_C int _gl_cxxalias_dummy
# endif
#else
# define _GL_CXXALIASWARN1(func,rettype,parameters_and_attributes) \
    _GL_EXTERN_C int _gl_cxxalias_dummy
#endif

#endif /* _GL_CXXDEFS_H */

/* The definition of _GL_WARN_ON_USE is copied here.  */
#ifndef _GL_WARN_ON_USE

# if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
/* A compiler attribute is available in gcc versions 4.3.0 and later.  */
#  define _GL_WARN_ON_USE(function, message) \
extern __typeof__ (function) function __attribute__ ((__warning__ (message)))
# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
/* Verify the existence of the function.  */
#  define _GL_WARN_ON_USE(function, message) \
extern __typeof__ (function) function
# else /* Unsupported.  */
#  define _GL_WARN_ON_USE(function, message) \
_GL_WARN_EXTERN_C int _gl_warn_on_use
# endif
#endif

/* _GL_WARN_ON_USE_CXX (function, rettype, parameters_and_attributes, "string")
   is like _GL_WARN_ON_USE (function, "string"), except that the function is
   declared with the given prototype, consisting of return type, parameters,
   and attributes.
   This variant is useful for overloaded functions in C++. _GL_WARN_ON_USE does
   not work in this case.  */
#ifndef _GL_WARN_ON_USE_CXX
# if 4 < __GNUC__ || (__GNUC__ == 4 && 3 <= __GNUC_MINOR__)
#  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
extern rettype function parameters_and_attributes \
     __attribute__ ((__warning__ (msg)))
# elif __GNUC__ >= 3 && GNULIB_STRICT_CHECKING
/* Verify the existence of the function.  */
#  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
extern rettype function parameters_and_attributes
# else /* Unsupported.  */
#  define _GL_WARN_ON_USE_CXX(function,rettype,parameters_and_attributes,msg) \
_GL_WARN_EXTERN_C int _gl_warn_on_use
# endif
#endif

/* _GL_WARN_EXTERN_C declaration;
   performs the declaration with C linkage.  */
#ifndef _GL_WARN_EXTERN_C
# if defined __cplusplus
#  define _GL_WARN_EXTERN_C extern "C"
# else
#  define _GL_WARN_EXTERN_C extern
# endif
#endif


#if !1

/* fake a poll(2) environment */
# define POLLIN      0x0001      /* any readable data available   */
# define POLLPRI     0x0002      /* OOB/Urgent readable data      */
# define POLLOUT     0x0004      /* file descriptor is writable   */
# define POLLERR     0x0008      /* some poll error occurred      */
# define POLLHUP     0x0010      /* file descriptor was "hung up" */
# define POLLNVAL    0x0020      /* requested events "invalid"    */
# define POLLRDNORM  0x0040
# define POLLRDBAND  0x0080
# define POLLWRNORM  0x0100
# define POLLWRBAND  0x0200

# if !GNULIB_defined_poll_types

struct pollfd
{
  int fd;                       /* which file descriptor to poll */
  short events;                 /* events we are interested in   */
  short revents;                /* events found on return        */
};

typedef unsigned long nfds_t;

#  define GNULIB_defined_poll_types 1
# endif

/* Define INFTIM only if doing so conforms to POSIX.  */
# if !defined (_POSIX_C_SOURCE) && !defined (_XOPEN_SOURCE)
#  define INFTIM (-1)
# endif

#endif


#if 1
# if 0
#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
#   undef poll
#   define poll rpl_poll
#  endif
_GL_FUNCDECL_RPL (poll, int, (struct pollfd *pfd, nfds_t nfd, int timeout));
_GL_CXXALIAS_RPL (poll, int, (struct pollfd *pfd, nfds_t nfd, int timeout));
# else
#  if !1
_GL_FUNCDECL_SYS (poll, int, (struct pollfd *pfd, nfds_t nfd, int timeout));
#  endif
_GL_CXXALIAS_SYS (poll, int, (struct pollfd *pfd, nfds_t nfd, int timeout));
# endif
_GL_CXXALIASWARN (poll);
#elif defined GNULIB_POSIXCHECK
# undef poll
# if HAVE_RAW_DECL_POLL
_GL_WARN_ON_USE (poll, "poll is unportable - "
                 "use gnulib module poll for portability");
# endif
#endif


#endif /* _GL_POLL_H */
#endif /* _GL_POLL_H */

bug#18508: Incomplete type pollfd

[Ludovic Courtès]

Andreas Enge <andreas@enge.fr> skribis:

> On Mon, Sep 22, 2014 at 10:43:27AM +0200, Ludovic Courtès wrote:
>> What libc version is this?
>
> The package is glibc-2.12-1.107.el6_4.5.x86_64.

Oh, OK.

>> It would have been great, if this is still possible, to post lib/poll.h.
>> Normally that file uses #include_next to get libc’s <poll.h>, but maybe
>> that mechanism somehow fails with old GCC versions.
>
> I just retried the compilation, and poll.h is attached. It contains
> #if 1 
> # include_next <poll.h>
> #endif

Normally that should be enough to get the ‘struct pollfd’ definition no?

Does something like this build correctly with ‘gcc -Wall -c’:

--8<---------------cut here---------------start------------->8---
#include <poll.h>

int
foo (struct pollfd *x)
{
  return x->events;
}
--8<---------------cut here---------------end--------------->8---

Thanks,
Ludo’.

bug#18508: Incomplete type pollfd

[Andreas Enge]

On Sat, Sep 27, 2014 at 11:41:09AM +0200, Ludovic Courtès wrote:
> Does something like this build correctly with ‘gcc -Wall -c’:
> 
> --8<---------------cut here---------------start------------->8---
> #include <poll.h>
> 
> int
> foo (struct pollfd *x)
> {
>   return x->events;
> }
> --8<---------------cut here---------------end--------------->8---

Yes, without any warning.

Andreas

bug#18507: Incomplete type pollfd

[Andy Wingo]

On Fri 19 Sep 2014 12:28, Andreas Enge <andreas@enge.fr> writes:

> On Fri, Sep 19, 2014 at 12:16:15PM +0200, Andreas Enge wrote:
>> gcc 4.4.7
>
> It seems to be a problem with the gcc version; with gcc-4.8.3, I get past
> this point. So maybe this bug report can be safely ignored.

I guess given the lack of followup that there is nothing to do here.  I
wish I understood the problem though!

Andy