How do I make Boost multithreading? - c++

I am trying to compile the latest Boost c++ libraries for Centos. I 've used bjam install and it has placed the libraries in /usr/lib and /usr/lib64.
The problem is I need the -mt variants for a specific application to run. I cannot understand in the documentation how to create the multithreading variants. :(
Please give me a hint!
Thanks!

-mt is just distribution specific extension.
either edit your config file or create symbolic link to libboost_thread
andrey#localhost:~$ ls -l /usr/lib/libboost_thread*
-rw-r--r-- 1 root root 174308 2010-01-25 10:36 /usr/lib/libboost_thread.a
lrwxrwxrwx 1 root root 41 2009-11-04 10:10 /usr/lib/libboost_thread-gcc41-mt-1_34_1.so.1.34.1 -> libboost_thread-gcc42-mt-1_34_1.so.1.34.1
-rw-r--r-- 1 root root 49912 2008-11-01 02:55 /usr/lib/libboost_thread-gcc42-mt-1_34_1.so.1.34.1
lrwxrwxrwx 1 root root 17 2010-01-27 18:32 /usr/lib/libboost_thread-mt.a -> libboost_thread.a
lrwxrwxrwx 1 root root 25 2010-01-27 18:32 /usr/lib/libboost_thread-mt.so -> libboost_thread.so.1.40.0
lrwxrwxrwx 1 root root 25 2010-01-27 18:32 /usr/lib/libboost_thread.so -> libboost_thread.so.1.40.0
-rw-r--r-- 1 root root 89392 2010-01-25 10:36 /usr/lib/libboost_thread.so.1.40.0

You can build all variations of the boost binary libraries using the --build-type=complete option. For example:
bjam --build-type=complete stage
This will put all library files into <your boost dir>/stage/lib/

Related

Undefined reference to `libbgp::BgpFsm::tick()'

I started working with c++ a few weeks ago, and I started a new project to start learning more. I'm encountering an issue with an external dependency. I'm trying to use a library called:
libbgp, and I installed it base on their documentation.
Here is my code:
https://gist.github.com/amb1s1/9b2c72294da0ec9416810c8686d3adce
Error:
/usr/bin/ld: /tmp/ccsdO32O.o: in function `ticker(libbgp::BgpFsm&)':
ambgp.cpp:(.text+0xa7): undefined reference to `libbgp::BgpFsm::tick()'
collect2: error: ld returned 1 exit status
I'm not sure if there is anything else that I have to do after installing the lib for the library to be accessible in my source code.
Update
I ran it with the -lbgp flag and when running it, i get the following error:
g++ -lbgp ambgp.cpp -o ambgp
Error:
./ambgp: error while loading shared libraries: libbgp.so.0: cannot open shared object file: No such file or directory
My Lib:
ls -l /usr/local/lib/
-rw-r--r-- 1 root root 10875880 Jan 18 16:56 libbgp.a
-rwxr-xr-x 1 root root 924 Jan 18 16:56 libbgp.la
lrwxrwxrwx 1 root root 15 Jan 18 16:56 libbgp.so -> libbgp.so.0.0.0
lrwxrwxrwx 1 root root 15 Jan 18 16:56 libbgp.so.0 -> libbgp.so.0.0.0
-rwxr-xr-x 1 root root 4291128 Jan 18 16:56 libbgp.so.0.0.0
drwxrwsr-x 3 root staff 4096 Dec 16 19:27 python3.7
echo $LD_LIBRARY_PATH
:/usr/local/lib
Before running the executable, you have to tell it where to find the libgdp.so file, if it is not stored in a standard place such as /usr/lib or /lib. Following should help you:
$ export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/usr/local/lib"
$ ./ambgp
If you do not want to export the LD_LIBRARY_PATH each time you start the shell manually, add the line to your /home/<user>/.bashrc file.
Additionally, i think the -lbgp flag should go after the source file in the compiler command (g++ ambgp.cpp -lbgp -o ambgp)
TL;DR :
ld states it cannot find libbgp.so.0, and you wrote in the comments that you found libbgp.so without a trailing .0. So, creating a symlink to the library could help too:
$ sudo ln -s /usr/local/lib/libbgp.so /usr/local/lib/libbgp.so.0
For linking, you need a library file without a trailing .0, but for loading, the library name must have a trailing .0.
The last thing to try is to directly specify the library location to the linker with -Wl,-rpath=/usr/local/lib (as you worked out already !)

Using Freetype library with CMake [duplicate]

I'm new to cmake, and I'm only using it to install opencv on my ubuntu linux.
Here's the command I ran: cmake -DCMAKE_BUILD_TYPE=Release DCMAKE_INSTALL_PREFIX=/home/jinha/OCV/source
Then it returns the error:
FATAL: In-source builds are not allowed. You should create separate directory for build files.
My current directory, ~/OCV/build/opencv, does contain the CMakefiles.txt file, so that's not the problem. I tried to change the directory in my command, but they all raise the same error. I saw the other answers on this issue, so I erased CMakeFiles directory and CMakeCache.txt file every time before I ran the command, but none of them worked.
Thanks.
It wants you to create a separate build directory (anywhere), and run cmake there. For example:
mkdir my_build_dir
cd my_build_dir
rm ../CMakeCache.txt
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/home/jinha/OCV/source
Note the .. in this example telling cmake where to look for the source.
In case you didn't remove CMakeCache.txt before building again, it will still show this error.
So, please remember to delete CMakeCache.txt first before running cmake.
After you have success downloaded and unzipped OpenCV sources from sources you need create simple command-file install.sh. For example, your working dir will be /home/user/myopencv
So /home/user/myopencv/install.sh will be contain next code:
#!/bin/bash
rm CMakeCache.txt
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=RELEASE -DCMAKE_INSTALL_PREFIX=/usr/local
make
make install
make clean
Next
chmod 777 install.sh
./install.sh
And after the all you will get those executable files:
root#cartman:/usr/local/bin# ls -las | grep opencv
32 -rwxr-xr-x 1 root root 29888 апр 20 18:10 opencv_annotation
244 -rwxr-xr-x 1 root root 247608 апр 20 18:10 opencv_createsamples
244 -rwxr-xr-x 1 root root 247504 апр 20 18:10 opencv_haartraining
20 -rwxr-xr-x 1 root root 18600 апр 20 18:10 opencv_performance
288 -rwxr-xr-x 1 root root 294592 апр 20 18:10 opencv_traincascade
16 -rwxr-xr-x 1 root root 14288 апр 20 18:10 opencv_version
60 -rwxr-xr-x 1 root root 61040 апр 20 18:10 opencv_visualisation
Enjoy!

Eclipse CDT Post-Build commands error

I have a C++ project and I´m using Eclipse CDT 3.8.1 as the IDE tool, with a workspace of 5 different projects...
One of my projects is a shared library, and at the end of compilation I want to copy its code to a test/bin directory for testing.
I´ve gone to Project Properties -> C/C++ Build -> Settings -> Build Steps and at "Post-build steps", "Command", I´ve added:
cp *.so ../../../bin
(OBS: ../../../bin is the correct path from the Debug folder - I´ve checked already).
What happens is that I get the following error on post build:
cp *.so ../../../bin
cp: cannot stat ‘*.so’: No such file or directory
I said: ok, this may be a permission problem, so I changed the post commands to:
whoami;ls -al; ls *.so;
And I got on Eclipse console:
whoami
aeidev
ls -al
total 264
drwxrwxr-x 3 aeidev aeidev 4096 Apr 25 15:55 .
drwxrwxr-x 5 aeidev aeidev 4096 Apr 22 16:27 ..
-rwxrwxr-x 1 aeidev aeidev 242556 Apr 25 15:55 libaeirtuaccess.so
-rw-rw-r-- 1 aeidev aeidev 1763 Apr 23 20:47 makefile
-rw-rw-r-- 1 aeidev aeidev 245 Apr 23 20:46 objects.mk
-rw-rw-r-- 1 aeidev aeidev 526 Apr 23 20:47 sources.mk
drwxrwxr-x 2 aeidev aeidev 4096 Apr 25 15:41 src
ls *.so
15:55:11 Build Finished (took 1s.80ms)
And them I changed again to ls *.so and I got:
ls -al *.so
ls: cannot access *.so: No such file or directory
15:57:50 Build Finished (took 715ms)
It´s a very strange behaviour. In the same workspace I have a different shared library and the original cp *.so works fine...
Any ideas of what´s going on here ?
Is it a known Eclipse bug ?
Thanks for helping...
I believe the commands are not executed in a shell by default, so wildcards are not evaluated. Try executing like /bin/sh -c 'cp *.so ../../../bin/'. Also you should use Eclipse's built-in variables to copy to the desired path.

g++ link to shared library not being compiled

I have these shared library files in /usr/local/lib:
libopenbabel.so
libopenbabel.so.4
libopenbabel.so.4.0.2
libopenbabel.so is actually a link to libopenbabel.so.4 and libopenbabel.so.4 is actually a link to libopenbabel.so.4.0.2
when I compile my file with this command:
g++ test.cpp -L/usr/local/lib -lopenbabel
and then try to run a.out, I get this error:
./a.out: error while loading shared libraries: libopenbabel.so.4: cannot open shared object file: No such file or directory
Implying that the compiler is finding libopenbabel.so but running into an error when following that link to libopenbabel.so.4 which is in the exact same directory. Any ideas on why this is happening / how I can fix it?
Output of ls -l in /usr/local/lib:
total 33772
drwxr-xr-x 7 root root 4096 Mar 22 01:24 .
drwxr-xr-x 10 root root 4096 Aug 20 2013 ..
drwxr-xr-x 3 root root 4096 Mar 21 23:45 cmake
lrwxrwxrwx 1 root root 13 Mar 21 23:45 libinchi.so -> libinchi.so.0
lrwxrwxrwx 1 root root 17 Mar 21 23:45 libinchi.so.0 -> libinchi.so.0.4.1
-rw-r--r-- 1 root root 3315565 Mar 22 01:04 libinchi.so.0.4.1
lrwxrwxrwx 1 root root 17 Mar 21 23:45 libopenbabel.so -> libopenbabel.so.4
lrwxrwxrwx 1 root root 21 Mar 21 23:45 libopenbabel.so.4 -> libopenbabel.so.4.0.2
-rw-r--r-- 1 root root 31232420 Mar 22 01:04 libopenbabel.so.4.0.2
drwxr-xr-x 3 root root 4096 Mar 21 23:45 openbabel
drwxr-xr-x 2 root root 4096 Mar 22 01:24 pkgconfig
drwxrwsr-x 4 root staff 4096 Mar 3 12:57 python2.7
drwxrwsr-x 3 root staff 4096 Dec 22 18:25 python3.2
Either set your LD_LIBRARY_PATH environment variable to contain /usr/local/lib or add /usr/local/lib to /etc/ld.so.conf and run ldconfig as root.
Also, run ldd a.out to check that dynamic linking works well on your app.
Read ld-linux(8), ldconfig(8), ldd(1)

Fail to compile c++ source to swc using Alchemy on Mac OS X Lion

When I tried to compile a [.cpp] file to [.swc] file, I got this:
dyld: Library not loaded: /usr/lib/libltdl.3.dylib
And I found that my libltdl is
Poechant:src poechant$ ls -l /usr/lib/libltdl.*
lrwxr-xr-x 1 root wheel 15 10 11 08:17 /usr/lib/libltdl.7.2.2.dylib -> libltdl.7.dylib
-rwxr-xr-x 1 root wheel 88848 10 11 08:17 /usr/lib/libltdl.7.dylib
lrwxr-xr-x 1 root wheel 15 10 11 08:17 /usr/lib/libltdl.dylib -> libltdl.7.dylib
How to solve it?
According to the post here
http://forums.adobe.com/message/3892045:
The following set of commands would work( i tested, too )
cd /usr/lib/
sudo ln -s libltdl.7.dylib libltdl.3.dylib