myvas::cmdout

The cmdout library provides facilities for executing shell commands and get their output before time runs out.

Getting Started

Import and link the library via CMake

include(FetchContent)
FetchContent_Declare(cmdout
	URL https://github.com/myvas/cmdout/archive/refs/tags/0.2.0.tar.gz
	DOWNLOAD_EXTRACT_TIMESTAMP ON
)
FetchContent_MakeAvailable(cmdout)

target_link_libraries(<your_target> PRIVATE cmdout)

Include the header file

#include <cmdout/cmdout.h>

Examples

C++17 on GNU/Linux Debian 11 (bullseye)

#include <cmdout/cmdout_ext.h>
#include <cassert>
//...
int main() {
	// function myvas::system()
	{
		auto result = myvas::system("exit 0");
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}
	{
		auto result = myvas::system("exit 1");
		std::cout << result << std::endl;
		assert(result.status() == EXIT_FAILURE);
	}
	{
		auto result = myvas::system("ls not-exist 2>&1");
		std::cout << result << std::endl;
		assert(result.status() == ENOENT);
	}
	{
		auto result = myvas::system_timeout("ls / -l", std::chrono::milliseconds(0)).exec();
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}
	{
		auto result = myvas::system_timeout_ms("ls / -l", 1);
		std::cout << result << std::endl;
		assert(result.status() == ETIME);
	}
	{
		auto result = myvas::system_timeout_ms("ls / -l", 9);
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}

	// class myvas::cmdout
	{
		auto result = myvas::cmdout().exec();
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}
	{
		auto result = myvas::cmdout("ls not-exist 2>&1").exec();
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}
	{
		auto result = myvas::cmdout("ls / -l", std::chrono::milliseconds(1)).exec();
		std::cout << result << std::endl;
		assert(result.status() == ETIME);
	}
	{
		auto result = myvas::cmdout("ls / -l", std::chrono::milliseconds(9)).exec();
		std::cout << result << std::endl;
		assert(result.status() == EXIT_SUCCESS);
	}
}

Tests

All tests passed (33 assertions in 3 test cases)

Benchmarks

./benchmarks/benchmarks
2023-09-06T13:07:51+08:00
Running ./benchmarks
Run on (4 X 2893.41 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x2)
  L1 Instruction 32 KiB (x2)
  L2 Unified 256 KiB (x2)
  L3 Unified 4096 KiB (x1)
Load Average: 1.81, 1.24, 0.94
------------------------------------------------------------
Benchmark                  Time             CPU   Iterations
------------------------------------------------------------
BM_std_system        1587179 ns        81671 ns         8562
BM_std_system_out    1751184 ns       147665 ns         4749
BM_myvas_system      1639949 ns       100367 ns         7086
BM_myvas_cmdout      1760044 ns        56635 ns        12510

For developers

FAQ 1. Could NOT find Doxygen (missing: dot) (found version "1.9.5")

We should install the doxygen and graphviz on the build/test/debug machine. (CMakeLists.txt Line: 119-123)

apt install doxygen
apt install graphviz

FAQ 2. How to install/upgrade cmake 3.27.0?

We should install the cmake 3.27.0 (or above) on the build/test/debug machine. Here are steps on Debian:

1.Check current version and location.

cmake --version
which cmake

2.Download the installation script.

wget -b -c --show-progress  https://github.com/Kitware/CMake/releases/download/v3.27.0/cmake-3.27.0-linux-x86_64.sh

3.Run the script to unzip files.

sudo mv cmake-3.27.0-linux-x86_64.sh /opt
cd /opt
sudo bash cmake-3.27.0-linux-x86_64.sh

4.Replace old symbolic links.

sudo rm /usr/local/bin/ccmake
sudo rm /usr/local/bin/cmake
sudo rm /usr/local/bin/cmake-gui
sudo rm /usr/local/bin/cpack
sudo rm /usr/local/bin/ctest
sudo ln /opt/cmake-3.27.0-linux-x86_64/bin/* /usr/local/bin

Known issues

• As of now, the feature is active on Linux, but it is not available for Windows, and there are no upcoming plans to make it compatible with Windows.