How to create alpha_encoder.exe (webm-tools) under msys2? - c++

I'm trying to compile alpha_encoder) (little utility of The WebM Project, under webm-tools).
I have a previous installation of msys2 (downloaded and configured by build_locally_with_various_option_prompts.bat) under c:\FFcompiler. It took its time, but I managed to compile ffmpeg, so I decided to use it (I think it will do). That's what I've done till now.
First, I cloned webm-tools under /cygdrive/c/FFcompiler/ffmpeg_local_builds/sandbox/win32/libvpx-1.4.0/third_party/. There's a Makefile so I tried to run make:
$ cd /cygdrive/c/FFcompiler/ffmpeg_local_builds/sandbox/win32/libvpx-1.4.0/third_party/
$ git clone https://chromium.googlesource.com/webm/webm-tools.git
$ cd webm-tools/alpha_encoder/
$ make
But g++ complains mkvparser.hpp doesn't exist. The command is
g++ -c -W -Wall -O3 -g -I../../libwebm alpha_encoder.cc -o alpha_encoder.o
After searching the web, it seems that webm-tools depends on libwebm, and expect finding it as a sibling folder of webm-tools. So...
$ cd ../..
$ git clone https://chromium.googlesource.com/webm/libwebm.git
$ cd libwebm
Now, what? README.libwebm tells that 'to cross compile libwebm for Windows using mingw-w64' first I must run cmake like this cmake -DCMAKE_TOOLCHAIN_FILE=path/to/libwebm/build/mingw-w64_toolchain.cmake path/to/libwebm. In my case:
cmake -DCMAKE_TOOLCHAIN_FILE=build/mingw-w64_toolchain.cmake .
And cmake cannot find i686-w64-mingw32-g++. After googling more, it seems the easiest way to fix this is to add bin of mingw-w64-i686 to PATH.
$ export PATH=/cygdrive/c/FFcompiler/ffmpeg_local_builds/sandbox/cross_compilers/mingw-w64-i686/bin:$PATH
After this, now cmake finishes successfully and creates a Makefile, but make stops with an error:
/cygdrive/c/FFcompiler/ffmpeg_local_builds/sandbox/win32/libvpx-1.4.0/third_part
y/libwebm/common/file_util.cc:44:39: error: 'tmpnam_s' was not declared in this
scope
errno_t err = tmpnam_s(tmp_file_name);
^
I've searched about the error but I'm stuck. What am I missing?

Related

How do I compile my C++ code with anaconda boost?

I have to use Anaconda provided compilers and their Boost package to compile my C++ code. I have a problem such that I do not know how to link properly during the compilation command.
To begin with: I create a dedicated anaconda env. with the following packages:
- boost-cpp=1.77.0
- compilers=1.3.0
These packages may be found here:
https://anaconda.org/conda-forge/compilers
https://anaconda.org/conda-forge/boost-cpp
Upon env. activation: double check which compiler I use:
$ which g++
/usr/share/miniconda3/envs/MYNAME/bin/g++
And then I would like to compile, but I don't know how to include boost libraries.
When I run:
$ g++ workflow/src/CODE.cpp -o workflow/bin/CODE -lm
Of course I get:
CODE.h:10:10: fatal error: boost/property_tree/info_parser.hpp: No such file or directory
10 | #include <boost/property_tree/info_parser.hpp>
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Nevermind, I have worked it out.
Although it might be useful for others so let's keep the solution in here:
g++ workflow/src/CODE.cpp -o workflow/bin/CODE -I$HOME/miniconda3/envs/MYNAME/include -lm

Compiling multiple C++ files. Calling a binary to run a code

I have 2 cpp files(with one main function) in /home/misha/proga/c++again folder. I built C/C++: g++ build active task and modified it to compile all files in the folder above. Now, I need to add one more task to call a binary. I think I should add one more entry in "tasks" to finally be able to run a code. Where can I read about how to write this second task? I am new to programming. Is my approach correct to run this code contained in two files? I also do not know where this binary lies. Is it tasks file in .vscode folder ?
I use Ubuntu 19.10 and VSC 1.46.1
In Terminal,
cd /home/misha/proga/c++again
Let's suppose your two cpp files are mainFile.cpp and file2.cpp
If g++ (so GCC) was not installed in your system, you can install it by running this command on the Terminal:
sudo apt-get install gcc g++
and, to compile the program (read about invoking GCC, you want warnings and debug information), write this command into the Terminal:
g++ -Wall -g mainFile.cpp file2.cpp -o yourprog
Then, you can run the program by typing:
./yourprog
It should work now. You could need to use the GDB debugger and GNU make (to be installed with sudo apt-get install gdb make)
Read also some C++ programming book and this C++ reference.
I do not understand your approach usualy your create a makefile and compile your cpp files
g++ -g -c -fpic -o name.o
at the end you link them
g++ name.o 2name.o and so on
If you create binarys you should store them in /usr/lib
and the name should libname.so you can acces them by using the -l argument

Why in my Linux, when current work directory is owned by root (e.g /usr/bin), then I cannot link any library while compiling c++?

If I write this code and saved as a.cpp at ~/Desktop
#include <memory>
int main(){}
then input to bash:
cd /usr/bin
g++ -g ~/Desktop/a.cpp -o ~/Desktop/a
then the g++ will output plenty of messy code of errors.
I have found the reason is because it don't have authority to link XX.so library.
But if I add a 'sudo' , or set CWD to the path owned by user, g++ will work properly, as follows:
sudo g++ -g ~/Desktop/a.cpp -o ~/Desktop/a
or
cd ~/Desktop
g++ -g ~/Desktop/a.cpp -o ~/Desktop/a
Why do this happen? or how can I fix this?
You don't want to generate code directly in /usr/bin.
You generate your code in your user folder, maybe create a sub-directory called cppwork or something like that.
cd
mkdir cppwork
cd cppwork
g++ -g a.cpp -o a
Once you compiled in your directory, then you copy the file using install which will also take care of stripping the debug if any (i.e. the -g says to keep debug info—stripping is not mandatory).
sudo install -s a /usr/bin/a
As you can see, the place where I use sudo is with the install command.
That being said, I never use those directly. Now a day, I use cmake which means everything works automatically. But that would be a different discussion.
Thanks for every one. I have found the reason. It's because there is an executable program named 'array' in /usr/bin. And when CWD is /usr/bin, the compiler regard this 'array' as the c++ header <array>, so compiling error.
Then I need to find out why the compiler includes /usr/bin by mistake.

Tensorflow Op: how to include libtensorflow_framework.so?

I followed the instructions of this tutorial:
https://www.tensorflow.org/extend/adding_an_op#implement_the_gradient_in_python.
There is this comment provided: g++ -std=c++11 -shared zero_out.cc -o zero_out.so -fPIC -I$TF_INC -I$TF_INC/external/nsync/public -L$TF_LIB -ltensorflow_framework -O2
But the linker cannot find -ltensorflow_framework (it should be a tensorflow_frameowork.so file!?)
After some research, I found following links:
https://github.com/tensorflow/tensorflow/issues/1569
https://github.com/eaplatanios/tensorflow_scala/issues/26 --> I downloaded the .jar and linked it via -l/pathto/tensorflow_framework.so, still the fatal error: tensorflow/core/framework/op_kernel.h: No such file or directory is not found.
https://github.com/tensorflow/tensorflow/issues/1270 last comment does not work and so does not help me.
I tried to search for sudo find /usr/. -name "tensorflow_framework.so" recursively but I could not find anything. Tensorflow is installed for sure via anaconda and I also cloned and compiled the repository from source.
How to find a way to include the -ltensorflow_framework?
One answer, I have found:
I have installed my python via anaconda2 and I always tried to find out TF_INC and TF_LIB when I activated my repository source activate <env>. and the could not found any ~/anaconda2/envs/tensorflow/lib/python2.7/site-packages/tensorflow
*.so files
This time I went out every python environment with the shell command source deactivate and I typed the following command
python -c 'import tensorflow as tf; print(tf.sysconfig.get_lib())'
Now, I got a different path: ~/anaconda2/lib/python2.7/site-packages/tensorflow, where the lib libtensorflow_framework.so is located.
In my case, the file libtensorflow_framework.so.1 existed inside my TF_LIB directory instead of libtensorflow_framework.so. In order to solve this issue, I had to create a symbolic link as follows:
ln -s libtensorflow_framework.so.1 libtensorflow_framework.so
Source: Tensorflow NotFoundError: libtensorflow_framework.so: cannot open shared file or directory
tensorflow_framework is not used before Tensorflow 1.4.1
When you call python from the shell make sure you are calling the right one:
TF_LIB = $(shell python -c 'import tensorflow; print(tensorflow.sysconfig.get_lib())')
or
TF_LIB = $(shell python3 -c 'import tensorflow; print(tensorflow.sysconfig.get_lib())')
To be more clear:
Get the path from python -c 'import tensorflow as tf; print(tf.sysconfig.get_lib())', and there is a libtensorflow_framework.so.1 inside the directory. Say /home/.../lib/python3.7/site-packages/tensorflow_core/libtensorflow_framework.so.1
Run ln -s /home/.../lib/python3.7/site-packages/tensorflow_core/libtensorflow_framework.so.1 /home/.../lib/python3.7/site-packages/tensorflow_core/libtensorflow_framework.so

Failing to compile GTest with Cygwin

I'm new to C++, I am trying to compile gtest with Cygwin. I have installed the GNU g++ compiler which works fine. I ran the following command on Cygwin:
g++ -I /cygdrive/c/devel/cpp/gtest/include -I /cygdrive/c/devel/cpp/gtest -pthread -c /cygdrive/c/devel/cpp/gtest/googletest/src/gtest-all.cc
/cygdrive/c/devel/cpp/gtest/googletest/src/gtest-all.cc:39:25: fatal error: gtest/gtest.h: No such file or directory
compilation terminated.
All the files seem to be in place, however the error does not go, any ideas why?
It looks like you have provided space between -I and path.
There should not be any space between -I and corresponding path.
It should be like
g++ -I/cygdrive/c/devel/cpp/gtest/include -I/cygdrive/c/devel/cpp/gtes..
Check it.