Implementation of multi-threading basic functionality

Data Structures
struct	wget_thread_st
struct	wget_thread_mutex_st
struct	wget_thread_cond_st

Functions
int	wget_thread_mutex_init (wget_thread_mutex *mutex)
int	wget_thread_mutex_destroy (wget_thread_mutex *mutex)
void	wget_thread_mutex_lock (wget_thread_mutex mutex)
void	wget_thread_mutex_unlock (wget_thread_mutex mutex)
int	wget_thread_cond_init (wget_thread_cond *cond)
int	wget_thread_cond_destroy (wget_thread_cond *cond)
int	wget_thread_cond_signal (wget_thread_cond cond)
int	wget_thread_cond_wait (wget_thread_cond cond, wget_thread_mutex mutex, long long ms)
int	wget_thread_start (wget_thread *thread, void *(*start_routine)(void *), void *arg, WGET_GCC_UNUSED int flags)
int	wget_thread_cancel (WGET_GCC_UNUSED wget_thread thread)
int	wget_thread_kill (WGET_GCC_UNUSED wget_thread thread, WGET_GCC_UNUSED int sig)
int	wget_thread_join (wget_thread *thread)
wget_thread_id	wget_thread_self (void)
bool	wget_thread_support (void)

Detailed Description

This is a wrapper around Gnulib's glthread functionality.

It currently supports Posix threads (pthreads), GNU Pth threads, Solaris threads and Windows threads.

Function Documentation

wget_thread_mutex_init()

int wget_thread_mutex_init

(

wget_thread_mutex *

mutex

)

Parameters

[in,out]

mutex

The mutex to initialize

Returns

0 on success, non-zero on failure

Initializes the mutex.

After usage, a call to wget_thread_mutex_destroy() frees the allocated resources.

wget_thread_mutex_destroy()

int wget_thread_mutex_destroy

(

wget_thread_mutex *

mutex

)

Parameters

[in,out]

mutex

The mutex to destroy

Returns

0 on success, non-zero on failure

Free's the mutex and it's resources.

After calling this function, the mutex cannot be used any more.

wget_thread_mutex_lock()

void wget_thread_mutex_lock

(

wget_thread_mutex

mutex

)

Parameters

[in]

mutex

The mutex to be locked

Creates a lock on the mutex.

To unlock the mutex, call wget_thread_mutex_unlock().

wget_thread_mutex_unlock()

void wget_thread_mutex_unlock

(

wget_thread_mutex

mutex

)

Parameters

[in]

mutex

The mutex to be unlocked

Unlocks the mutex.

wget_thread_cond_init()

int wget_thread_cond_init

(

wget_thread_cond *

cond

)

Parameters

[in,out]

cond

The conditional to initialize

Returns

0 on success, non-zero on failure

Initializes the conditional cond.

After usage, a call to wget_thread_cond_destroy() frees the allocated resources.

wget_thread_cond_destroy()

int wget_thread_cond_destroy

(

wget_thread_cond *

cond

)

Parameters

[in,out]

cond

The conditional to destroy

Returns

0 on success, non-zero on failure

Free's the conditional cond and it's resources.

After calling this function, cond cannot be used any more.

wget_thread_cond_signal()

int wget_thread_cond_signal

(

wget_thread_cond

cond

)

Parameters

[in]

cond

The conditional to signal a condition

Returns

0 on success, non-zero on failure

Wakes up one (random) thread that waits on the conditional.

wget_thread_cond_wait()

int wget_thread_cond_wait	(	wget_thread_cond	cond,
		wget_thread_mutex	mutex,
		long long	ms )

Parameters

[in]	cond	The conditional to wait for
[in]	mutex	The mutex needed for thread-safety
[in]	ms	The wait timeout in milliseconds

Returns

0 on success, non-zero on failure

Waits for a condition with a max. timeout of ms milliseconds.

To wait forever use a timeout lower or equal then 0.

wget_thread_start()

int wget_thread_start	(	wget_thread *	thread,
		void *	start_routine (*)(void *),
		void *	arg,
		WGET_GCC_UNUSED int	flags )

Parameters

[out]	thread	The thread variable to be initialized
[in]	start_routine	The thread function to start
[in]	arg	The argument given to start_routine
[in]	flags	Currently unused

Returns

0 on success, non-zero on failure

Start start_routine as own thread with argument arg.

wget_thread_cancel()

int wget_thread_cancel

(

WGET_GCC_UNUSED wget_thread

thread

)

Parameters

[in]

thread

Thread to cancel

Returns

0 on success, non-zero on failure

Currently a no-op function, since it's not portable.

wget_thread_kill()

int wget_thread_kill	(	WGET_GCC_UNUSED wget_thread	thread,
		WGET_GCC_UNUSED int	sig )

Parameters

[in]	thread	Thread to send the signal to
[in]	sig	Signal to send

Returns

0 on success, non-zero on failure

Currently a no-op function, since it's not portable.

wget_thread_join()

int wget_thread_join

(

wget_thread *

thread

)

Parameters

[in]

thread

Thread to wait for

Returns

0 on success, non-zero on failure

Wait until the thread has been stopped.

This function just waits - to stop a thread you have take your own measurements.

wget_thread_self()

wget_thread_id wget_thread_self

(

void

)

Returns

The thread id of the caller.

wget_thread_support()

bool wget_thread_support

(

void

)

Returns

Whether libwget supports multi-threading on this platform or not.