[FFmpeg-devel] [PATCH v3] lavd/decklink_common: Fix error caused by -Werror=missing-prototypes

[Richard Kern]

> On Jun 27, 2016, at 4:58 AM, Michael Niedermayer <michael at niedermayer.cc> wrote:
> 
> On Sun, Jun 26, 2016 at 08:24:49PM -0400, Rick Kern wrote:
>> decklink_common.cpp includes a .cpp file from the DeckLink API which fails
>> to build because there are non-static functions in the included .cpp file.
>> This disables the missing-prototypes error so the file can be included.
>> 
>> Signed-off-by: Rick Kern <kernrj at gmail.com>
>> ---
>> libavdevice/Makefile | 2 ++
>> 1 file changed, 2 insertions(+)
>> 
>> diff --git a/libavdevice/Makefile b/libavdevice/Makefile
>> index 585827b..e281825 100644
>> --- a/libavdevice/Makefile
>> +++ b/libavdevice/Makefile
>> @@ -19,6 +19,8 @@ OBJS-$(CONFIG_BKTR_INDEV)                += bktr.o
>> OBJS-$(CONFIG_CACA_OUTDEV)               += caca.o
>> OBJS-$(CONFIG_DECKLINK_OUTDEV)           += decklink_enc.o decklink_enc_c.o decklink_common.o
>> OBJS-$(CONFIG_DECKLINK_INDEV)            += decklink_dec.o decklink_dec_c.o decklink_common.o
> 
>> +$(SUBDIR)decklink_common.o: CXXFLAGS += -Wno-error=missing-prototypes
> 
> Is this portable ?
> is there some posix document or similar that says that this
> is supported by all compilers ?

configure adds the -Werror=missing-prototypes only if it’s supported by the compiler. Instead, I could add -Wno-error=… to CFLAGS only if it’s supported.

> 
> and in what directory are these system headers that cause the problem?
> is this directory a system header directory ?
> what compiler fails to suppress warnings from system headers ?

They’re not in a system header directory. It fails to build with clang when it’s added as a user include directory, but it does build with -isystem. I’ve seen this issue floating around the internet, so this would make building the decklink code a little easier.

> 
> also:
> http://clang.llvm.org/docs/UsersManual.html#controlling-diagnostics-in-system-headers
> 
> [...]
> -- 
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