How do I execute a command and get the output of the command within C++ using POSIX?

Question

I am looking for a way to get the output of a command when it is run from within a C++ program. I have looked at using the system() function, but that will jus

Answer 1

Getting both stdout and stderr (and also writing to stdin, not shown here) is easy peasy with my pstreams header, which defines iostream classes that work like popen:

#include 
#include 
#include 

int main()
{
  // run a process and create a streambuf that reads its stdout and stderr
  redi::ipstream proc("./some_command", redi::pstreams::pstdout | redi::pstreams::pstderr);
  std::string line;
  // read child's stdout
  while (std::getline(proc.out(), line))
    std::cout << "stdout: " << line << '\n';
  # if reading stdout stopped at EOF then reset the state:
  if (proc.eof() && proc.fail())
    proc.clear();
  // read child's stderr
  while (std::getline(proc.err(), line))
    std::cout << "stderr: " << line << '\n';
}