I am on macOS Catalina (10.15.5) and I have installed FFTW using brew install fftw. I also have GCC (version 10.2.0) installed which is symlinked to the commands I am using below.
I am able to compile and run a simple C++ program like so:
g++-10 test.cpp -L/usr/local/lib -I/usr/local/include -lfftw3 -lm
But, I had to modify the environment variable CPATH to make this work.
I am unable to get a simple Fortran FFTW example to work (I am using this one). The command I am using to compile is:
gfortran-10 test.f90 -L/usr/local/lib -I/usr/local/include -lfftw3 -lm
The error I get is as follows:
Undefined symbols for architecture x86_64:
"__gfortran_os_error_at", referenced from:
_MAIN__ in ccRvJaEQ.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status
If I understand correctly, the linking step fails. Any inputs on how I might find the relevant paths that I may have to pass to the compiler would be very helpful. I searched for solutions and I wasn't able to find one. But, in case I missed something obvious, I apologise.
Thanks to msi_gerva's helpful hints through comments, I was able to solve the issue by downloading FFTW and compiling it to a custom directory following the installation directions.
Now, the linking doesn't fail if I pass the new locations of the libraries to gfortran like so:
gfortran-10 test.f90 -L/new/path/to/lib -I/new/path/to/include -lfftw3 -lm
Since /usr/local/ is the default installation path, it's possible that there is a mixing up of the FFTW library files from previous installations.
Related
I am currently trying to compile a cpp program with openmp. From what I have read online this is the command that I need to use for indeed using openmp on apple silicon:
g++ -Xpreprocessor -fopenmp -I/opt/homebrew/Cellar/libomp/14.0.6/include -L/usr/local/lib -lomp heat2D.cpp
I have installed everything required for openmp (libomp,llvm,etc...) but it gives me this error:
ld: library not found for -lomp
clang: error: linker command failed with exit code 1 (use -v to see invocation)
In addition if try to remove the lomp flag:
g++ -Xpreprocessor -fopenmp -I/opt/homebrew/Cellar/libomp/14.0.6/include heat2D.cpp
this is the error i get:
Undefined symbols for architecture arm64:
"_omp_set_num_threads", referenced from:
_main in heat2D-0b5aaa.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Since you mention that you installed GCC (and LLVM) via Homebrew, the problem is probably (as Jim Cownie suggested) that when you type "g++", you are running the default link to Apple's LLVM installation (which, alas, does not support OpenMP).
The problem is that Homebrew installs its versions of the compiler binary commands using versioned names -- e.g., "g++-12" if you installed the latest version of GCC. So you have to use those names if you want to run the Homebrew versions. (They are probably installed in /opt/homebrew/bin/ in your case, since you have an Apple Silicon Mac.)
(I haven't installed Homebrew's version of LLVM, but it's probably a similar situation for that as well, since you wouldn't want it to overwrite Apple's LLVM commands.)
With the new XCode/Swift release comes the ability to use binary dependencies. This seems to me to be an ideal time to create an SPM package for FFMpeg.
However, while I've spent the last year learning to code i Swift, I'm actually not all that familiar with how to build libraries, especially those as complex as FFmpeg with all the configurable libraries and third-party dependencies.
There's kewlbear's iOS build scripts, but these are for iOS/tvOS and ideally an FFMpeg SPM package would be usable for MacOS also. It's also not updated for the newest Xcode and Swift versions.
My personal interest is simply in audio and I don't need a lot of bells and whistles, but I figure the ideal situation would be a full package with the entire source and whatever dependencies it needs, and then when it's used as a package dependency, the compiler will just use the parts it needs.
I guess my question is...how would I ideally compile the ffmpeg code for this purpose. I'm trying to follow the directions for compiling yourself, but I'm stuck at the point of compiling gettext because I'm not sure if I should follow the directions (in the gettext source code) for compiling a fat binary for multiple architectures, and when I try to run:
./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
CPP="gcc -E" CXXCPP="g++ -E"
I get the following error:
checking whether the C compiler works... no configure: error: in
`/Users/nolainecrusher/Downloads/FFMpeg-source/gettext-0.21/gettext-runtime':
configure: error: C compiler cannot create executables See
`config.log' for more details configure: error: ./configure failed for
gettext-runtime
and config.log doesn't really tell me anything useful:
This is what I see at the end of the log:
mkdir_p='$(MKDIR_P)' oldincludedir='/usr/include' pdfdir='${docdir}'
prefix='/usr/local' program_transform_name='s,x,x,' psdir='${docdir}'
sbindir='${exec_prefix}/sbin' sharedstatedir='${prefix}/com' subdirs='
gettext-runtime libtextstyle gettext-tools' sysconfdir='${prefix}/etc'
target_alias=''
I feel like maybe I'm going about this the wrong way, but I'm not sure what the right way is.
See the following:
A Swift wrapper package for FFmpeg and
A C wrapper package for FFmpeg
SwiftFFmpeg assumes ffmpeg is installed locally and will link with those libraries. Also, SwiftFFmpeg uses CFFmpeg as a package dependency, and your app can use SwiftFFmpeg as a dependency.
If you want to see a build script for compiling ffmpeg (x86_64 and arm64), check out my own audio player project.
I'm trying to compile a very small amount of C source into a library that I can use in XCode for an iOS application.
The files are a single .c file and three header files. I'm very new to C, and no matter what I try I can't seem to get them to compile into a library that supports iOS architectures.
The files depend on the openssl library, and I've got that installed and working fine.
I just need to know the process of compiling these four files into a single library. I've found a plethora of information on the subject online, but I can't decipher which parts are necessary for what I'm trying to do.
I've tried the following:
gcc -fPIC -c main.c
gcc -shared -o mylib.so main.o -lcrypto -lssl
which seems to compile it for x86_64, (I've not tested the resulting file, just checked it's arch).
I've also tried
./configure --disable-shared --enable-utf8 --host=arm-apple-darwin CFLAGS="-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.1.sdk" CXXFLAGS="-arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.1.sdk" LDFLAGS="-L." CC="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc" CXX="/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++"
which only gives me errors
checking for arm-apple-darwin-gcc... no
checking for gcc... gcc
checking whether the C compiler works... no
configure: error: in `/Users/nathanf/compilec':
configure: error: C compiler cannot create executables
I've been scouring the internet for the last few days trying to figure this out, but it's so convoluted to cross compile just a few files and I'm frustrated so I came here for some input.
Any help would be greatly appreciated.
I'm trying to compile OpenCV version 2.3.1 on an Ubuntu 11.10 following instructions described here. I'm getting following error. Can't understand what is happening... /usr/local/lib/libavcodec.a exists but linker can't link against it, or something else?
error:
[ 20%] Built target pch_Generate_opencv_highgui
Linking CXX shared library ../../lib/libopencv_highgui.so
/usr/bin/ld: /usr/local/lib/libavcodec.a(avpacket.o): relocation R_X86_64_32S against `av_destruct_packet'
can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libavcodec.a: could not read symbols: Bad value
collect2: ld returned 1 exit status
The problem is that you are attempting to link libopencv_highgui.so with libavcodec.a. The latter is built from code compiled without -fPIC (which is quite usual), and such code can not be linked into shared libraries on x86_64.
Your choices are:
Obtain libavcodec.so and arrange to link against it, or
Remove libavcodec or -lavcodec from the link line completely.
For the first, you most likely just need to install libavcodec-dev package.
If you do the second, you will still have to arrange for symbols that libopencv_highgui.so needs from libavcodec to be available at runtime. You can achieve that by linking the main executable with libavcodec (either archive or shared variant).
my take would be that, first run sudo apt-get remove libavcodec , then re-install with sudo apt-get install libopencv-dev
I once had similar issue, and the above resolved it
Running a 64-bit version of Ubuntu you have to configure and build ffmpeg with
./configure --enable-shared --enable-pic
as it is described in step 7b and 8b
having this problem on installing several things on my mac,
i think this problem is coming from upgrading my leopard to snow leopard. Also this problem also is linked with macports i think.
/usr/local/lib/libz.1.dylib, file was built for i386 which is not the architecture being linked (x86_64)
Any ideas?
Update
To be more specific this happens on installing nokogiri gem
and the log looks like:
xslt_stylesheet.c:127: warning: passing argument 1 of ‘Nokogiri_wrap_xml_document’ with different width due to prototype
cc -dynamic -bundle -undefined suppress -flat_namespace -o nokogiri.bundle
html_document.o html_element_description.o html_entity_lookup.o html_sax_parser_context.o nokogiri.o xml_attr.o xml_attribute_decl.o xml_cdata.o xml_comment.o xml_document.o xml_document_fragment.o xml_dtd.o xml_element_content.o xml_element_decl.o xml_encoding_handler.o xml_entity_decl.o xml_entity_reference.o xml_io.o xml_libxml2_hacks.o xml_namespace.o xml_node.o xml_node_set.o xml_processing_instruction.o xml_reader.o xml_relax_ng.o xml_sax_parser.o xml_sax_parser_context.o xml_sax_push_parser.o xml_schema.o xml_syntax_error.o xml_text.o xml_xpath_context.o xslt_stylesheet.o -L. -L/usr/local/lib -L/opt/local/lib -L/usr/local/lib -L/usr/lib -L. -lruby -lexslt -lxslt -lxml2 -lpthread -ldl -lobjc
ld: in /usr/local/lib/libz.1.dylib, file was built for i386 which is not the architecture being linked (x86_64)
collect2: ld returned 1 exit status
make: *** [nokogiri.bundle] Error 1
This is not about MacPorts:
zlib is installed as i386, so you have to build it for x86-64. Here's how to do it:
Update: As Nick says in his comment, you first have to remove old zlib files: sudo rm /opt/local/lib/libz*
Download zlib source code from its webpage
Extract the source, and open a terminal in source location
./configure, make and sudo make install
If it still doesn't work, remove ruby and install it again (you can do it with RVM)
Hope it helped you.
You might have x86_64 compiled zlib installed in
/usr/local/opt/zlib/ or alternatively do a brew install zlib
this will install zlib in /usr/local/Cellar/.
Temporary remove libz.* from /usr/local/lib/ into a backup folder.
Do gem install nokogiri -v '<version>' --with-zlib-dir=<zlib directory path from step 1>
Nokogiri must be installed by now. Restore the backup libz again.
It is a macport migration to snow leopard issue, sadly you have to reinstall macports and all the ports to have the right architecture. Read the wiki here: https://trac.macports.org/wiki/Migration