How can I execute a system command with C++ and capture its output and the status. It should look something like this:
Response launch(std::string command);
int main()
{
auto response = launch("pkg-config --cflags spdlog");
std::cout << "status: " << response.get_status() << '\n'; // -> "status: 0"
std::cout << "output: " << response.get_output() << '\n'; // -> "output: -DSPDLOG_SHARED_LIB -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL"
}
Using std::system
you can only get status. I also tried this solution but it only captures the output and it seems to be very "hacky" and not safe. There must be a better way to do it but I haven't found one yet. If there isn't a simple and portable solution, I would also use a library.
I found a way with redirecting the output to a file and reading from it:
#include <string>
#include <fstream>
#include <filesystem>
struct response
{
int status = -1;
std::string output;
};
response launch(std::string command)
{
// set up file redirection
std::filesystem::path redirection = std::filesystem::absolute(".output.temp");
command.append(" &> \"" + redirection.string() + "\"");
// execute command
auto status = std::system(command.c_str());
// read redirection file and remove the file
std::ifstream output_file(redirection);
std::string output((std::istreambuf_iterator<char>(output_file)), std::istreambuf_iterator<char>());
std::filesystem::remove(redirection);
return response{status, output};
}
Still seems a bit "hacky" but it works. I would love to see a better way without creating and removing files.
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