Compile glib based single file source
gcc glib_test.c -ggdb3 -fsanitize=address pkg-config --cflags --libs glib-2.0 -o glib_testCompile glib based single file source having GStreamer functionality
gcc glib_test.c -ggdb3 -fsanitize=address pkg-config --cflags --libs glib-2.0 pkg-config --cflags --libs gstreamer-1.0 -o glib_test
If you are using following code
#include <sys/stat.h>
struct stat foo = {0};
in the modern c++, and compiler warnings (GCC: -Wall -Wextra) it is likely that you
will find following warning
<source>:4:21: warning: missing initializer for member 'stat::st_ino' [-Wmissing-field-initializers]
4 | struct stat foo = {0};
| ^
It is due to new syntax introduced in C++11 for uniform initialization. It means that
{0} is doing initlization of just first data member of struct stat. To fix this warning
you have to use struct stat foo {};
GCC 5.1 introduced a new implementation of libstdc++ to meet C++11 requirements for std::string (copy-on-write) and std::list (std::list::size() is O(n)).
Mixing of different versions ABI will likely to cause a crash.
Macro _GLIBCXX_USE_CXX11_ABI can be used to select an appropriate implementation of libstdc++.
-D_GLIBCXX_USE_CXX11_ABI=1 will pick new ABI (libstdc++11).
-D_GLIBCXX_USE_CXX11_ABI=0 will pick old ABI (libstdc++).
New ABI has been set to default since GCC 6.1
Issue gcc -v to find out whether compiler is using new ABI or not.
gcc -vUsing built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.4.0-1ubuntu1~20.04.1' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-9 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-9-Av3uEd/gcc-9-9.4.0/debian/tmp-nvptx/usr,hsa --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.1)
https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html
To install pre-built cppcheck: http://cppcheck.sourceforge.net/
sudo apt-get update sudo apt-get install cppcheck
In case, you want to use latest cppcheck, download and build it from the source code
wget https://github.com/danmar/cppcheck/archive/2.1.tar.gz tar zxvf 2.1.tar.gz cd cppcheck-2.1 mkdir build cd build cmake ..
P.S: In case you are interested for cppcheck GUI use cmake -DBUILD_GUI=ON ..
make sudo make install
Once installation is complete.
which cppcheck /usr/local/bin/cppcheck cppcheck --version Cppcheck 2.1
Build your cpp project with cmake and pass on an extra parameter -DCMAKE_EXPORT_COMPILE_COMMANDS=TRUE to cmake. It will produce compile_commands.json file in your build folder for the project.
Execute cppcheck -p </path/to/folder/having/compile_command.json>.
To use it in VSCode add following to the tasks.json
{
"label": "Run cppCheck",
"command": "/usr/local/bin/cppcheck",
"args": [
"--project=${workspaceRoot}/build/compile_commands.json"
],
"problemMatcher": "$gcc",
}
Ref: https://gist.github.com/aakbar5/268a2072138345893b7f82590dcc3d26
| // A simple example of how dup2 can be used | |
| const char* msg = "Text written by standard file descriptor\n"; | |
| int fd = open("dup2_test.txt", O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); | |
| write(fd, msg, strlen(msg)); | |
| /* Map stdout to our file */ | |
| dup2(fd, STDOUT_FILENO); | |
| printf("Text written by dup @ stdout file descriptor\n"); | |
| close(fd); |
Use following instructions to install IWYU (https://include-what-you-use.org/) on Ubuntu 18.04.3 LTS:
sudo apt-get update sudo apt-get install -y build-essential cmake git zlib1g-dev libncurses5-dev llvm-6.0-dev libclang-6.0-dev libclang-6.0-dev clang-6.0 git clone https://github.com/include-what-you-use/include-what-you-use.git iwyu.git cd iwyu.git git checkout clang_6.0 mkdir -p build cd build cmake -DIWYU_LLVM_ROOT_PATH=/usr/lib/llvm-6.0 .. make make install
Once installation is complete, you will find `include-what-you-need`
# include-what-you-use --version include-what-you-use 0.10 (git:a1878c4) based on clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
To execute include-what-you-need:
Build your cpp project with cmake and pass on an extra parameter -DCMAKE_EXPORT_COMPILE_COMMANDS=TRUE to cmake. It will produce `compile_commands.json` file in your build folder for the project.
Execute iwyu_tool.py -p </path/to/folder/having/compile_command.json>. It may take time depending upon the code size.
fix_includes can be used to apply recommended changes.
To use it in VSCode add following to the tasks.json
{
"label": "Run iwyu",
"command": "iwyu_tool.py",
"args": [
"-p",
"${workspaceRoot}/build"
],
"presentation": {
"echo": true,
"reveal": "always",
"focus": true,
"panel": "shared",
"showReuseMessage": true,
"clear": false
},
"problemMatcher": "$gcc"
}
Ref: https://gist.github.com/aakbar5/268a2072138345893b7f82590dcc3d26
If you are working with C/C++ in VSCode, you will find that VSCode keeps on showing
"${workspaceFolder}/build/compile_commands.json" could not be found. 'includePath' from c_cpp_properties.json will be used instead.
This message is generated by vscode-cpptools. Although it is an optional file however vscode-cpptools keeps on showing error message that it is missing.
This message can easily be fixed if you are using CMake. To do so simply add following to your CMake configuration file.
# Generate compile_commands.json set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
Some of C++17 filesystem module examples can be found here. These examples include:
C++17 supports Filesystem library (https://en.cppreference.com/w/cpp/filesystem). If you are using it in your application you have to pass -lstdc++fs to g++ to make use of it. Otherwise you will end up with undefined reference(s) to std::filesystem::
| By default enum can't be as bitfield | |
| typedef enum _type_ { | |
| CAT = 0, | |
| DOG, | |
| UNKNOWN | |
| } TYPE; | |
| typedef struct _animal { | |
| TYPE type : 2; | |
| }; | |
| GCC ((Sourcery CodeBench 2015.17-10) 5.2.0) will show error "width of 'type' exceeds its type" | |
| Use -fno-short-enums to get rid of this. Details: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0774b/chr1411640303038.html |
asadakbar 