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Date: Tue, 5 May 2015 09:05:49 -0300
From: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
To: Felix Janda <felix.janda@posteo.de>
Cc: linux-media@vger.kernel.org
Subject: Re: [PATCH 2/4] Test for ioctl() function signature
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In-Reply-To: <20150125203625.GB11999@euler>
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Em Sun, 25 Jan 2015 21:36:25 +0100
Felix Janda <felix.janda@posteo.de> escreveu:

> On glibc, ioctl has the signature ioctl(int, unsigned long int, ...).
> On musl, libc and according to POSIX it is ioctl(int, int, ...).
> Add a configure test adapted from gnulib's ioctl.m4 to make the
> DL_PRELOAD libraries work for both signatures.


This patch breaks compilation on Fedora:

v4l2convert.c:130:45: error: conflicting types for 'ioctl'
 LIBV4L_PUBLIC int ioctl(int fd, int request, ...)
                                             ^
In file included from v4l2convert.c:37:0:
/usr/include/sys/ioctl.h:41:12: note: previous declaration of 'ioctl' was here
 extern int ioctl (int __fd, unsigned long int __request, ...) __THROW;
            ^

> 
> Signed-off-by: Felix Janda <felix.janda@posteo.de>
> ---
>  configure.ac              | 12 ++++++++++++
>  lib/libv4l1/v4l1compat.c  |  4 ++++
>  lib/libv4l2/v4l2convert.c |  4 ++++
>  3 files changed, 20 insertions(+)
> 
> diff --git a/configure.ac b/configure.ac
> index 4156559..00136d7 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -116,6 +116,18 @@ gl_VISIBILITY
>  AC_CHECK_HEADERS([sys/klog.h])
>  AC_CHECK_FUNCS([klogctl])
>  
> +AC_CACHE_CHECK([for ioctl with POSIX signature],
> +  [gl_cv_func_ioctl_posix_signature],
> +  [AC_COMPILE_IFELSE(
> +     [AC_LANG_PROGRAM(
> +        [[#include <sys/ioctl.h>]],
> +        [[int ioctl (int, int, ...);]])
> +     ],
> +     [gl_cv_func_ioctl_posix_signature=yes],
> +     [gl_cv_func_ioctl_posix_signature=no])
> +  ])
> +AC_DEFINE([HAVE_POSIX_IOCTL], [1], [test x$gl_cv_func_ioctl_posix_signature = xyes])
> +
>  AC_CHECK_FUNCS([__secure_getenv secure_getenv])
>  
>  # Check host os
> diff --git a/lib/libv4l1/v4l1compat.c b/lib/libv4l1/v4l1compat.c
> index 07240c1..282173b 100644
> --- a/lib/libv4l1/v4l1compat.c
> +++ b/lib/libv4l1/v4l1compat.c
> @@ -93,7 +93,11 @@ LIBV4L_PUBLIC int dup(int fd)
>  	return v4l1_dup(fd);
>  }
>  
> +#ifdef HAVE_POSIX_IOCTL
> +LIBV4L_PUBLIC int ioctl(int fd, int request, ...)
> +#else
>  LIBV4L_PUBLIC int ioctl(int fd, unsigned long int request, ...)
> +#endif
>  {
>  	void *arg;
>  	va_list ap;
> diff --git a/lib/libv4l2/v4l2convert.c b/lib/libv4l2/v4l2convert.c
> index b65da5e..c79f9da 100644
> --- a/lib/libv4l2/v4l2convert.c
> +++ b/lib/libv4l2/v4l2convert.c
> @@ -121,7 +121,11 @@ LIBV4L_PUBLIC int dup(int fd)
>  	return v4l2_dup(fd);
>  }
>  
> +#ifdef HAVE_POSIX_IOCTL
> +LIBV4L_PUBLIC int ioctl(int fd, int request, ...)
> +#else
>  LIBV4L_PUBLIC int ioctl(int fd, unsigned long int request, ...)
> +#endif
>  {
>  	void *arg;
>  	va_list ap;