Ubuntu13.04, g ++ 4.7, and Pthread implement multi-thread simulation to implement download progress bar

Ubuntu13.04, g ++ 4.7, Pthread implements multi-thread simulation to achieve download progress bar: # include & lt; pthread. h & gt; # include & lt; stdlib. h & gt; # include & lt; unistd. h & gt; # include & lt; iostream & gt; # include & lt; sys/times. h & gt; // use pthread to implement multithreading: one thread simulates download, and one

Ubuntu 13.04, g ++ 4.7, and Pthread implement multi-thread simulation to achieve download progress bar:

# Include
# Include
# Include
# Include
# Include
// Implement multiple threads in pthread: one thread simulates the download and one thread reads the current progress.

// The parameter used by the thread to pass the Parameter
Struct Args {
Int * length_ptr;
Pthread_rwlock_t * rwlock_ptr;
};

Void * download (void * args ){
// Printf ("args address = % p \ n", args );
Args args_object = * (Args *) args;
Args * a = & args_object;
Printf ("start_download OK \ n ");
Printf ("before while length = % d \ n", * a-> length_ptr );
// Printf ("before while length = % p \ n", a-> length_ptr );
While (* a-> length_ptr> 0 ){
// Printf ("in while length = % d \ n", * a-> length_ptr );
// Printf ("in while length = % p \ n", a-> length_ptr );
Int number = rand () % 100;
Pthread_rwlock_wrlock (a-> rwlock_ptr );
* A-> length_ptr-= number;
Printf ("after length-% d; length = % d \ n", number, * a-> length_ptr );
Pthread_rwlock_unlock (a-> rwlock_ptr );
Sleep (1 );
}
Return NULL;
}

Class Ftp {
Private:
Int length;
Static const int LENGTH = 10000000;
Pthread_rwlock_t rwlock;
Public:
Ftp (){
Length = LENGTH;
Int err = pthread_rwlock_init (& rwlock, NULL );
If (err! = 0 ){
// Error
Fprintf (stderr, "Error! \ N ");
}
}
~ Ftp (){
Pthread_rwlock_destroy (& rwlock );
}
Pthread_t start_download (){
Pthread_t thread_id;
Args * a = new Args (); // The thread passing parameter has a problem on the stack, so only one new
A-> length_ptr = & length;
A-> rwlock_ptr = & rwlock;

// Printf ("in start_download and before pthread_create: length = % d \ n", * a-> length_ptr );
// Printf ("in start_download and before pthread_create: length = % p \ n", a-> length_ptr );
// Printf ("in start_download (): args address = % p \ n", );
Int err = pthread_create (& thread_id, NULL, download, );
// Printf ("in start_download and before pthread_create: length = % p \ n", a-> length_ptr );
If (err! = 0 ){
// Error
Fprintf (stderr, "Error! \ N ");
Return-1;
}
Return thread_id;
}
Int get_length (){
Int len =-1;
Pthread_rwlock_rdlock (& rwlock );
Len = length;
Pthread_rwlock_unlock (& rwlock );
Return len;
}
};

Void * test_thread_fun (void * args ){
Ftp * ftp_ptr = static_cast (Args); // The same is true for this thread parameter, except that pthread_join ensures that ftp in main has no destructor.
While (ftp_ptr-> get_length ()> 0 ){
Printf ("read length from test_thread_fun: length = % d \ n", ftp_ptr-> get_length ());
// Sleep (rand () % 5 );
Sleep (1 );
}
}

Int main (){
Srand (0 );
// There is still a lot to do for this program
Ftp ftp;
Pthread_t thread_id = ftp. start_download ();
Pthread_t id;
// Test thread
Int err = pthread_create (& id, NULL, test_thread_fun, & ftp );
If (err! = 0 ){
// Error
Fprintf (stderr, "Error! \ N ");
Return-1;
}

// Wait thread_id exit
Pthread_join (thread_id, NULL );
Return 0;
}

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