Question

    # configure for i386 build
./configure \
--cc=/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc \
--as='gas-preprocessor.pl /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc' \
--sysroot=/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator4.3.sdk \
--extra-ldflags=-L/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator4.3.sdk/usr/lib/system \
--target-os=darwin \
--arch=i386 \
--cpu=i386 \
--extra-cflags='-arch i386' \
--extra-ldflags='-arch i386' \
--prefix=compiled/i386 \
--enable-cross-compile \
--disable-armv5te \
--disable-ffmpeg \
--disable-ffplay \
--disable-ffserver \
--disable-ffprobe \
--disable-doc

the below will build ffmpeg static libraries for i386. but i don’t know about the option’s means such as “–extra-cflags”、”–extra-ldflags”、”–sysroot=”、”–as=”.

who can tell me about those options mean ? where i can find the details explanation？

thanks . I am waitting for your help.

Answer 1

You can always run the configure script as configure --help; it will print a usage statement and information about many of the accepted parameters — and usually, hopefully, the package-specific ones of interest.

That said, --extra-cflags would provide extra command-line switches for the C compiler, --as would give the path to the assembler, --sysroot would give an alternate installation directory, and --extra-ldflags would provide extra flags for the linker. Those are all fairly advanced, and you’re unlikely to need to use them.