Class child

boost::process::child

Synopsis

// In header: <boost/process/child.hpp>


class child {
public:
  // construct/copy/destruct
  explicit child(pid_t &);
  child(child &&);
  template<typename... Args> explicit child(Args &&...);
  child() = default;
  child & operator=(child &&);
  ~child();

  // private member functions
  void detach();
  void join();
  bool joinable();
  native_handle_t native_handle() const;
  int exit_code() const;
  pid_t id() const;
  bool running();
  bool running(std::error_code &) noexcept;
  void wait();
  void wait(std::error_code &) noexcept;
  template<typename Rep, typename Period> 
    bool wait_for(const std::chrono::duration< Rep, Period > &);
  bool wait_for(const std::chrono::duration< Rep, Period > &, 
                std::error_code &) noexcept;
  template<typename Clock, typename Duration> 
    bool wait_until(const std::chrono::time_point< Clock, Duration > &);
  bool wait_until(const std::chrono::time_point< Clock, Duration > &, 
                  std::error_code &) noexcept;
  bool valid() const;
  explicit operator bool() const;
  bool in_group() const;
  bool in_group(std::error_code &) const noexcept;
  void terminate();
  void terminate(std::error_code &) noexcept;
};

Description

The main class to hold a child process. It is simliar to std::thread, in that it has a join and detach function.

	Note
	The destructor will call terminate on the process if not joined or detached without any warning.

`child` public construct/copy/destruct

```
explicit child(pid_t & pid);
```
Construct the child from a pid.

Note

There is no guarantee that this will work. The process need the right access rights, which are very platform specific.
```
child(child && lhs);
```
Move-Constructor.
```
template<typename... Args> explicit child(Args &&... args);
```
Construct a child from a property list and launch it The standard version is to create a subprocess, which will spawn the process.
```
child() = default;
```
Construct an empty child.
```
child & operator=(child && lhs);
```
Move assign.
```
~child();
```
Destructor.

Note

Will call terminate (without warning) when the child was neither joined nor detached.

`child` private member functions

```
void detach();
```
Detach the child, i.e. let it run after this handle dies.
```
void join();
```
Join the child. This just calls wait, but that way the naming is similar to std::thread
```
bool joinable();
```
Check if the child is joinable.
```
native_handle_t native_handle() const;
```
Get the native handle for the child process.
```
int exit_code() const;
```
Get the exit_code. The return value is without any meaning if the child wasn't waited for or if it was terminated.
```
pid_t id() const;
```
Get the Process Identifier.
```
bool running();
```
Check if the child process is running.
```
bool running(std::error_code & ec) noexcept;
```
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
```
void wait();
```
Wait for the child process to exit.
```
void wait(std::error_code & ec) noexcept;
```
This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<typename Rep, typename Period> 
  bool wait_for(const std::chrono::duration< Rep, Period > & rel_time);

Wait for the child process to exit for a period of time.

Returns:

True if child exited while waiting.

bool wait_for(const std::chrono::duration< Rep, Period > & rel_time, 
              std::error_code & ec) noexcept;

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<typename Clock, typename Duration> 
  bool wait_until(const std::chrono::time_point< Clock, Duration > & timeout_time);

Wait for the child process to exit until a point in time.