[FFmpeg-devel] [PATCH 4/5] avfilter: avoid zero arguments to variadic macro

Michael Niedermayer michael at niedermayer.cc
Sat Oct 24 19:48:17 CEST 2015

On Sat, Oct 24, 2015 at 03:52:25PM +0200, Nicolas George wrote:
> Le tridi 3 brumaire, an CCXXIV, Ganesh Ajjanagadde a écrit :
> > Thanks for the super quick review. Will apply shortly. Do you (or
> > others) think adding -Wgnu-zero-variadic-macro-arguments to configure
> > is a good idea?
> Considering that each additional option takes ~15 ms in configure on a
> fairly powerful box, not counting maintenance burden, I would say rather no.

about 10ms here with
    time ./configure
about 1.5ms here with
    time ./configure --cc='ccache gcc'  --tempprefix=/home/michael/ffconftemp

also we could speed configure up with something like this:
(or a more generic "all before each" checker)

diff --git a/configure b/configure
index a38b290..6fa3273 100755
--- a/configure
+++ b/configure
@@ -5637,6 +5637,9 @@ disabled iconv || check_func_headers iconv.h iconv || check_lib2 iconv.h iconv -
 enabled debug && add_cflags -g"$debuglevel" && add_asflags -g"$debuglevel"

 # add some useful compiler flags if supported
+if ! check_cflags -Wdeclaration-after-statement -Wall -Wdisabled-optimization -Wpointer-arith -Wredundant-decls \
+                  -Wwrite-strings -Wtype-limits -Wundef -Wmissing-prototypes -Wno-pointer-to-int-cast -Wstrict-prototypes -Wempty-body ; then
 check_cflags -Wdeclaration-after-statement
 check_cflags -Wall
 check_cflags -Wdisabled-optimization
@@ -5649,6 +5652,9 @@ check_cflags -Wmissing-prototypes
 check_cflags -Wno-pointer-to-int-cast
 check_cflags -Wstrict-prototypes
 check_cflags -Wempty-body
+#Note, if you add a check_cflags here, also add it to the if above
 enabled extra_warnings && check_cflags -Winline


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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