Please, is someone familiar with Boehm GC?
I want to use it in the word-count app of Phoenix (https://github.com/kozyraki/phoenix), but I fail to modify the Makefile to include the GC library.
On the documentation page of Boehm, they only provide a simple c example and a command to compile it from the GC directory tree. I can't find any tutorial on how to link it with an existing project.
Thanks
The following steps should help you:
ensure libgc is installed on your host, e.g. on Ubuntu type like this: sudo apt install libgc-dev
your source files (which call GC_* functions) should include <gc.h>.
add -lgc to LIBS variable in the Makefile
Related
I'm building a relatively simple C extension to count pixels in a PNG file using libpng; I built the original version in C and it compiles (and works) fine in Cygwin with the command:
gcc -o shadow_counter shadow_counter.c -lpng
If I don't include the "-lpng" command it won't compile and kicks out a bunch of errors when trying to read the libpng functions ("undefined reference to `png_sig_cmp' ", etc.)
In order to package it for ruby, I put together the gemspec and files and folders and build it into a gem:
gem build shadow_png.gemspec
Then I head over to Powershell and install the gem:
gem install shadow_png-0.0.1.gem
If I leave out the libpng stuff, it installs fine and talks to Ruby the way it's supposed to. But once I start trying to reference the libpng functions and try to install it, it starts kicking out the SAME errors that I saw above (undefined reference to `png_sig_cmp' etc.). So my theory is that somehow the linking command -lpng isn't included.
How do I include these instructions as part of the process? Is it something I need to add to the gemspec? Or the command to build the gem? Or does it have to happen in the gem installation?
Thanks!
I think you're looking for the have_library method, to be placed in your extconf.rb file.
i.e.
abort 'Missing PNG library.' unless have_library('png')
The title states the problem statement: I'm trying to create a CMake project utilizing the libwebsocket library, but I can't find any information for doing so.
Is there anyone who have tried this? A simple CMakeLists.txt for e.g. the test-server program would be much appreciated!
I've compiled and installed the library on my Ubuntu 14.04 machine.
EDIT: I would also like to know if anyone has experience in using the libwebsocket lib w/ C++?
EDIT 2:
After using #evadeflow's answer I'm able to run cmake and build the project. However now I get the following runtime error:
And here's an ls of the /usr/local/lib/ folder
It seems like the libwebsockets.so.7 file is not found?
From CMake:
${LIB_WEBSOCKETS_INCLUDE_DIRS} = /usr/local/lib
${LIB_WEBSOCKETS_INSTALL_DIR} = /usr/local
EDIT 3:
Solved edit 2 by:
Editing the file /etc/ld.so.conf and add /usr/local/lib.
Reference: https://lonesysadmin.net/2013/02/22/error-while-loading-shared-libraries-cannot-open-shared-object-file/
If you've already installed libwebsockets, something like this ought to work:
cmake_minimum_required(VERSION 2.8)
find_package(PkgConfig)
pkg_check_modules(LIB_WEBSOCKETS REQUIRED libwebsockets)
get_filename_component(
LIB_WEBSOCKETS_INSTALL_DIR
${LIB_WEBSOCKETS_LIBRARY_DIRS}
DIRECTORY
)
add_executable(
test-server
test-server/test-server.c
test-server/test-server-http.c
test-server/test-server-dumb-increment.c
test-server/test-server-mirror.c
test-server/test-server-status.c
test-server/test-server-echogen.c
)
target_link_libraries(
test-server
${LIB_WEBSOCKETS_LIBRARIES}
)
set_target_properties(
test-server
PROPERTIES
INCLUDE_DIRECTORIES
${LIB_WEBSOCKETS_INCLUDE_DIRS}
LINK_FLAGS
"-L${LIB_WEBSOCKETS_LIBRARY_DIRS}"
COMPILE_DEFINITIONS
INSTALL_DATADIR="${LIB_WEBSOCKETS_INSTALL_DIR}/share"
)
This is basically a stripped-down version of what's in the CMakeLists.txt file from the libwebsockets github project, without all the platform- and build-specific conditionals.
I hope this is enough to satisfy your request for a 'simple' CMakeLists.txt example. I tested it with CMake version 2.8.12.2; it should work fine as-is if you've installed libwebsockets to its default prefix of /usr/local; however, if you installed to a different location, you will need to set PKG_CONFIG_PATH in the environment from which you invoke cmake.
Also, as explained in the CMake documentation, you will need to replace DIRECTORY with PATH in the get_filename_component() invocation if you're using CMake 2.8.11 or earlier.
UPDATE: Regarding the file not found error from your follow-up comment, this is almost certainly due to libwebsocket.so[.7] not being on the linker's default path. There are at least three ways to fix this, but the easiest way to verify that this is the problem would be to just launch the app from the terminal using:
$ LD_LIBRARY_PATH=/usr/local/lib ./test-server
If it works, you know that was the issue. (Oops—I see you've figured it out in the meantime. Yeah, updating /etc/ld.so.conf is another way. Or, you can force CMake to link to the static version of libwebsockets [as described in this answer] is another. But I like your solution best.)
UPDATE: One thing that wasn't mentioned about /etc/ld.so.conf is that you generally need to run sudo /sbin/ldconfig after editing it in order to update the shared library cache. And—when setting non-default paths for a particular application—many people consider it good form to add a new 'sub-config file' in /etc/ld.so.conf.d rather than edit the global ldconfig file. (For the case of adding /usr/local/lib, though, this is such a common requirement I'd be inclined to dump it in the global config, which is what lots of Linux distros do, anyway.)
I am trying to have a scheme with my library that is coherent and usable/reusable.
I work in a team where we work with continuous integration but sometimes I need to use old version of the same library. That's because some part of the software are not updated for using the new version.
I'm actually in the middle of a headache understanding how to use cmake for having something like this:
PATH/Library/Processor/Library_X/Version/static_library_and_includes
Where Library is a common name where to put my stuff
Processor could be attiny24, atmega, lxpXXXX, etc
Library_X is the name of the library
Version a progressive number from 0 to X
static_library_and_includes the static libraries built within that cmake module and the include files needed for using it.
How can I do this using cmake?
I work with different microprocessor crosscompiling with gcc. This is not a problem.
I work with static library, this is not a problem.
I can install them in the right directory. Not a problem
I can't ask the executable to link to the right .a file. Sometimes cmake pick the right one, sometimes not.
Can you please give me a hint on how you guys do it?
thank in advance
Andrea
See the search paths here: https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure .
CMake will find packages in directories named name*, so you can install to <prefix>/FizzBuzz-1.0.0 and <prefix>/FizzBuzz-2.0.0.
As long as each as a correct ConfigVersion.cmake file, it should do what you want.
You'll have to forgive me as I'm a bit new at C development. I'm working through the awesome guide found at c.learncodethehardway.com, so bear with me.
I'm trying to write a simple program which uses libbson to read and write a BSON tree to and from disk. In the past, I've usually just done apt-get install openssl-dev or the like to install headers on my system, but libbson is kind of new and doesn't exist in a deb form yet. Plus, I'd like my project to ship with it statically compiled-in for now until it becomes more widely available.
I know fairly basic things like the general format of a Makefile and how to write fairly simple stuff in C. How and where would I include the source code of libbson into my project to by statically compiled into my executables?
(Using gcc and would like to encapsulate compilation into a Makefile)
gcc -static your_program.c -L ./LIB -lbson -o your_program
where libbson is stored inside ./LIB.
Just spend 3 straight hours trying to solve the java.lang.UnsatisfiedLinkError: no jtokyocabinet in java.library.path problem in Eclipse in Linux.
Downloaded TC and TC-Java sources,
Built them both using ./config --prefix=/usr (so everything "JNI" related should be in /usr/lib)
Set the LD_LIBRARY_PATH=/usr/lib and CLASSPATH="$CLASSPATH:/usr/local/lib/tokyocabinet.jar" and exported both in .profile
Imported tokyocabinet.jar into the project.
Am I missing a setting other than the proper -Djava.library.path=. settings? I can't even find anything on the net about jtokyocabinet on the web or in the documentation. What's the secret sauce to getting this thing to work?
try to make a link to libjtokyocabinet.so...0 in your JAVA_HOME/jre/lib/i386.
it is because your code can not find tokyocabinet's *.so and *.a files, usually they are in /usr/local/lib, run the following command:
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
and then try your code again.
Have the same problem, in my case, using OpenSUSE 12.3 64 bits and Eclipse.
First, the kyotocabinet-java package can be downloaded from this repository:
http://download.opensuse.org/repositories/devel:/libraries:/c_c++/openSUSE_12.3/
This package provide /usr/lib64/libjkyotocabinet.so.1.1.0 that is the library used by the kyotocabinet jar you can get from maven or the official site.
Looking for this lib I found that there is created a slink:
xxxx#xxxx:/usr/lib64> ls -al /usr/lib64/libjkyoto*
/usr/lib64/libjkyotocabinet.so.1 -> libjkyotocabinet.so.1.1.0
/usr/lib64/libjkyotocabinet.so.1.1.0
I just created a new slink without the ".1" at the end...
sudo ln -s libjkyotocabinet.so.1.1.0 libjkyotocabinet.so
/usr/lib64/libjkyotocabinet.so -> /usr/lib64/libjkyotocabinet.so.1.1.0
And all worked alright, seems that
System.loadLibrary("jkyotocabinet");
don't work if the library name is ended with something different to ".so"
Yes, you're missing something. Eclipse controls its own classpath, so whatever you set up in the environment outside Eclipse is likely not to have any effect.
You need to go into the properties for your project, find the "Build Path" settings and add the path to your tc.jar (or jars) to your build path there.
It may be easier to set up a /lib directory within your eclipse project, copy your tokyo jar there and add that to your build path. That way, it becomes part of your project (and can move from Eclipse installation to Eclipse installation) rather than being an external system dependency.