Async::FdWatch Class Reference

A class for watching file descriptors. More...

#include <AsyncFdWatch.h>

List of all members.

Public Types

• enum FdWatchType { FD_WATCH_RD, FD_WATCH_WR }

  The type of the file descriptor watch. More...
  

Public Member Functions

• FdWatch (int fd, FdWatchType type)

  Constructor.
  

• ~FdWatch (void)

  Destructor.
  

• int fd (void) const

  Return the file descriptor being watched.
  

• FdWatchType type (void) const

  Return the type of this watch.
  

• void setEnabled (bool enabled)

  Enable or disable the watch.
  

• bool isEnabled (void) const

  Check if the watch is enabled or not.
  

Public Attributes

• SigC::Signal1< void, FdWatch * > activity

  Signal to indicate that the descriptor is active.
  

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Detailed Description

A class for watching file descriptors.

Author:

Tobias Blomberg

Date:

2003-03-19

Use this class to watch a file descriptor for activity. The example below creates a read watch on the standard input file descriptor. That is, every time a character is typed on the keyboard (or something is piped to the application) the onActivity method in instance this of class MyClass will be called. In the handler function, the data on the file descriptor should be read. Otherwise the handler function will be called over and over again.

Note:

Since the stdin is line buffered, the ENTER key has to be pressed before anything will be shown.

#include <unistd.h>
#include <cstdio>
#include <iostream>
#include <AsyncCppApplication.h>
#include <AsyncFdWatch.h>

using namespace std;
using namespace Async;

class MyClass : public SigC::Object
{
  public:
    MyClass(void)
    {
      stdin_watch = new FdWatch(STDIN_FILENO, FdWatch::FD_WATCH_RD);
      stdin_watch->activity.connect(slot(this, &MyClass::onActivity));
    }
    
    ~MyClass(void)
    {
      delete stdin_watch;
    }

  private:
    FdWatch *stdin_watch;
    
    void onActivity(FdWatch *watch)
    {
      char buf[1024];
      int cnt = read(watch->fd(), buf, sizeof(buf)-1);
      if (cnt == -1)
      {
        perror("read");
        Application::app().quit();
        return;
      }
      buf[cnt] = 0;
      cout << "Read from STDIN: " << buf << endl;
    }
};

int main(int argc, char **argv)
{
  CppApplication app;
  MyClass my_class;
  app.exec();
}

Definition at line 119 of file AsyncFdWatch.h.

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Member Enumeration Documentation

enum Async::FdWatch::FdWatchType

The type of the file descriptor watch. Enumerator: FD_WATCH_RD  File descriptor watch for incoming data. FD_WATCH_WR  File descriptor watch for outgoing data. Definition at line 125 of file AsyncFdWatch.h.

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Constructor & Destructor Documentation

Async::FdWatch::FdWatch (  int  fd, FdWatchType  type )

Constructor. Add the given file descriptor to the watch list and watch it for incoming data (FD_WATCH_RD) or write buffer space available (FD_WATCH_WR). Parameters: fd  The file descriptor to watch type  The type of watch to create (see FdWatchType)

Async::FdWatch::~FdWatch (  void   )

Destructor.

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Member Function Documentation

int Async::FdWatch::fd (  void   )  const [inline]

Return the file descriptor being watched. Returns: Returns the file descriptor Definition at line 151 of file AsyncFdWatch.h.

bool Async::FdWatch::isEnabled (  void   )  const [inline]

Check if the watch is enabled or not. Returns: Returns true if the watch is enabled, or else false. Definition at line 170 of file AsyncFdWatch.h.

void Async::FdWatch::setEnabled (  bool  enabled  )

Enable or disable the watch. Parameters: enabled  Set to true to enable the watch or false to disable it.

FdWatchType Async::FdWatch::type (  void   )  const [inline]

Return the type of this watch. Returns: Returns the type (see FdWatchType) Definition at line 157 of file AsyncFdWatch.h.

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Member Data Documentation

SigC::Signal1<void, FdWatch*> Async::FdWatch::activity

Signal to indicate that the descriptor is active. Parameters: watch  Pointer to the watch object Definition at line 176 of file AsyncFdWatch.h.

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The documentation for this class was generated from the following file:

• AsyncFdWatch.h

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