[FFmpeg-devel] [PATCH] Made appropriate changes to be able to successfully build C++ files using a Visual C++ build on Windows
Hendrik Leppkes
h.leppkes at gmail.com
Thu Apr 13 12:10:57 EEST 2017
On Thu, Apr 13, 2017 at 11:04 AM, Aaron Levinson <alevinsn at aracnet.com> wrote:
> On 4/13/2017 1:27 AM, Hendrik Leppkes wrote:
>> On Thu, Apr 13, 2017 at 10:23 AM, Aaron Levinson <alevinsn at aracnet.com> wrote:
>>> diff --git a/configure b/configure
>>> index b2fc781..6112b9b 100755
>>> --- a/configure
>>> +++ b/configure
>>> @@ -3637,8 +3637,10 @@ case "$toolchain" in
>>> cl_major_ver=$(cl 2>&1 | sed -n 's/.*Version \([[:digit:]]\{1,\}\)\..*/\1/p')
>>> if [ -z "$cl_major_ver" ] || [ $cl_major_ver -ge 18 ]; then
>>> cc_default="cl"
>>> + cxx_default="cl"
>>> else
>>> cc_default="c99wrap cl"
>>> + cxx_default="c99wrap cl"
>>> fi
>>> ld_default="$source_path/compat/windows/mslink"
>>> nm_default="dumpbin -symbols"
>>> @@ -3983,7 +3985,7 @@ probe_cc(){
>>> _cc=$2
>>> first=$3
>>>
>>> - unset _type _ident _cc_c _cc_e _cc_o _flags _cflags
>>> + unset _type _ident _cc_c _cc_e _cc_o _cxx_o _flags _cflags
>>> unset _ld_o _ldflags _ld_lib _ld_path
>>> unset _depflags _DEPCMD _DEPFLAGS
>>> _flags_filter=echo
>>> @@ -4156,6 +4158,7 @@ probe_cc(){
>>> fi
>>> _cc_o='-Fo$@'
>>> _cc_e='-P -Fi$@'
>>> + _cxx_o='-Fo$@'
>>> _flags_filter=msvc_flags
>>> _ld_lib='lib%.a'
>>> _ld_path='-libpath:'
>>> @@ -4196,6 +4199,7 @@ cflags_noopt=$_cflags_noopt
>>> add_cflags $_flags $_cflags
>>> cc_ldflags=$_ldflags
>>> set_ccvars CC
>>> +set_ccvars CXX
>>>
>>> probe_cc hostcc "$host_cc"
>>> host_cflags_filter=$_flags_filter
>>
>> Technically this just happens to work by accident because CC_O and
>> CXX_O get the same value, which is probably fine for all C++ compilers
>> we currently support.
>> set_ccvars always uses the _cc_o variable to set whatever namespace
>> you requested (_cxx_o is never used), so you could remove the _cxx_o
>> handling from probe_cc entirely and it would still work.
>>
>> Full CXX probing through probe_cc would be the most complete solution,
>> but probably overkill?
>>
>> - Hendrik
>
> Yes, I realize now that my use of _cxx_o had no effect, and it was simply the use of set_ccvars CXX that caused the CXX_ variables to be updated. I would tend to agree that full CXX probing is probably overkill given that there are only are few C++ files in ffmpeg, and those files have to do with Decklink, which is only supported on a few operating systems as well.
>
> I also realize now that this patch is more general than one that just applies to MSVC, although, in practice, the change will only benefit the Intel compiler, in addition to MSVC. Hopefully, I won't be asked to separate out the set_ccvars CXX line into a separate patch :-)
>
> Here is hopefully the final version of the patch with updated comments to reflect the more general nature of the patch.
>
> Thanks,
> Aaron Levinson
>
> ----------------------------------------------------------------------
>
> From 415f1f233eb963318d436fe272c3b80dda9d2d4d Mon Sep 17 00:00:00 2001
> From: Aaron Levinson <alevinsn at aracnet.com>
> Date: Thu, 13 Apr 2017 01:45:23 -0700
> Subject: [PATCH] Made appropriate changes to be able to successfully build C++ files using a Visual C++ build on Windows
>
> Purpose: Made appropriate changes to be able to successfully
> build C++ files using a Visual C++ build on Windows. Note that this is a
> continuation of the "fixes w32pthreads to support C++" aspect of Kyle
> Schwarz's "Remove pthread dependency" patch that is available at
> https://patchwork.ffmpeg.org/patch/2654/ . This patch wasn't accepted, and
> as far as I can tell, there was no follow-up after it was rejected.
>
> Notes: Used Visual Studio 2015 (with update 3) for this. Altered
> approach for specifying -Fo$@ in configure based on code review from
> Hendrik Leppkes for first version of patch.
>
> Comments:
>
> -- compat/w32pthreads.h: Made appropriate changes to w32pthreads.h to
> get it to build when it is being included in a C++ file and built
> with Visual C++. This is mostly a copy of Kyle Schwarz's patch as
> described above.
>
> -- configure:
> a) Now calling set_ccvars CXX to cause the various CXX_ variables to
> be setup properly. For example, with MSVC (Microsoft Visual C++),
> this causes CXX_O to be set to -Fo$@ instead of using the default
> value. The default value does not work with Visual C++. This
> change will also have the impact of correcting CXX_O (and possibly
> CXX_C) for other compilers, although this is really only relevant
> for the Intel compiler, in addition to MSVC.
> b) Now using cl for the C++ compiler for the MSVC toolchain. This is
> currently only relevant for building the
> Blackmagic/Decklink-related files under avdevice.
> ---
> compat/w32pthreads.h | 24 ++++++++++++------------
> configure | 3 +++
> 2 files changed, 15 insertions(+), 12 deletions(-)
>
> diff --git a/compat/w32pthreads.h b/compat/w32pthreads.h
> index 0c9a7fa..a6c699b 100644
> --- a/compat/w32pthreads.h
> +++ b/compat/w32pthreads.h
> @@ -77,7 +77,7 @@ typedef struct pthread_cond_t {
>
> static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
> {
> - pthread_t *h = arg;
> + pthread_t *h = (pthread_t*)arg;
> h->ret = h->func(h->arg);
> return 0;
> }
> @@ -270,7 +270,7 @@ static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_
> }
>
> /* non native condition variables */
> - win32_cond = av_mallocz(sizeof(win32_cond_t));
> + win32_cond = (win32_cond_t*)av_mallocz(sizeof(win32_cond_t));
> if (!win32_cond)
> return ENOMEM;
> cond->Ptr = win32_cond;
> @@ -288,7 +288,7 @@ static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_
>
> static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
> {
> - win32_cond_t *win32_cond = cond->Ptr;
> + win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
> /* native condition variables do not destroy */
> if (cond_init)
> return 0;
> @@ -305,7 +305,7 @@ static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
>
> static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
> {
> - win32_cond_t *win32_cond = cond->Ptr;
> + win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
> int have_waiter;
>
> if (cond_broadcast) {
> @@ -337,7 +337,7 @@ static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
>
> static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
> {
> - win32_cond_t *win32_cond = cond->Ptr;
> + win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
> int last_waiter;
> if (cond_wait) {
> cond_wait(cond, mutex, INFINITE);
> @@ -369,7 +369,7 @@ static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mu
>
> static av_unused int pthread_cond_signal(pthread_cond_t *cond)
> {
> - win32_cond_t *win32_cond = cond->Ptr;
> + win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
> int have_waiter;
> if (cond_signal) {
> cond_signal(cond);
> @@ -400,17 +400,17 @@ static av_unused void w32thread_init(void)
> HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
> /* if one is available, then they should all be available */
> cond_init = (void (WINAPI*)(pthread_cond_t *))
> - GetProcAddress(kernel_dll, "InitializeConditionVariable");
> + GetProcAddress((HMODULE)kernel_dll, "InitializeConditionVariable");
> cond_broadcast = (void (WINAPI*)(pthread_cond_t *))
> - GetProcAddress(kernel_dll, "WakeAllConditionVariable");
> + GetProcAddress((HMODULE)kernel_dll, "WakeAllConditionVariable");
> cond_signal = (void (WINAPI*)(pthread_cond_t *))
> - GetProcAddress(kernel_dll, "WakeConditionVariable");
> + GetProcAddress((HMODULE)kernel_dll, "WakeConditionVariable");
> cond_wait = (BOOL (WINAPI*)(pthread_cond_t *, pthread_mutex_t *, DWORD))
> - GetProcAddress(kernel_dll, "SleepConditionVariableCS");
> + GetProcAddress((HMODULE)kernel_dll, "SleepConditionVariableCS");
> initonce_begin = (BOOL (WINAPI*)(pthread_once_t *, DWORD, BOOL *, void **))
> - GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
> + GetProcAddress((HMODULE)kernel_dll, "InitOnceBeginInitialize");
> initonce_complete = (BOOL (WINAPI*)(pthread_once_t *, DWORD, void *))
> - GetProcAddress(kernel_dll, "InitOnceComplete");
> + GetProcAddress((HMODULE)kernel_dll, "InitOnceComplete");
> #endif
>
One more comment that I missed earlier (sorry), GetModuleHandle
returns the type HMODULE, can't you just change the type of kernel_dll
to match that, and avoid the casts here?
> }
> diff --git a/configure b/configure
> index b2fc781..43f0938 100755
> --- a/configure
> +++ b/configure
> @@ -3637,8 +3637,10 @@ case "$toolchain" in
> cl_major_ver=$(cl 2>&1 | sed -n 's/.*Version \([[:digit:]]\{1,\}\)\..*/\1/p')
> if [ -z "$cl_major_ver" ] || [ $cl_major_ver -ge 18 ]; then
> cc_default="cl"
> + cxx_default="cl"
> else
> cc_default="c99wrap cl"
> + cxx_default="c99wrap cl"
> fi
> ld_default="$source_path/compat/windows/mslink"
> nm_default="dumpbin -symbols"
> @@ -4196,6 +4198,7 @@ cflags_noopt=$_cflags_noopt
> add_cflags $_flags $_cflags
> cc_ldflags=$_ldflags
> set_ccvars CC
> +set_ccvars CXX
>
> probe_cc hostcc "$host_cc"
> host_cflags_filter=$_flags_filter
This looks ok now, thanks.
- Hendrik
More information about the ffmpeg-devel
mailing list