vl_condition_pthread.c File Reference

#include <pthread.h>

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Functions
vl_condition	vlConditionNew (void)
	Creates and initializes a new condition variable.
void	vlConditionDelete (vl_condition cond)
	De-initializes and deletes a condition variable.
void	vlConditionWait (vl_condition cond, vl_mutex mutex)
	Waits on a condition variable.
vl_bool_t	vlConditionWaitTimeout (vl_condition cond, vl_mutex mutex, vl_ularge_t millis)
	Waits on a condition variable with a timeout.
void	vlConditionSignal (vl_condition cond)
	Signals a condition variable, waking up at least one thread waiting on it.
void	vlConditionBroadcast (vl_condition cond)
	Broadcasts a condition variable to wake up all waiting threads.

Function Documentation

vlConditionBroadcast()

void vlConditionBroadcast

(

vl_condition

cond

)

Broadcasts a condition variable to wake up all waiting threads.

Contract

• Ownership: Unchanged.
• Lifetime: Unchanged.
• Thread Safety: Thread-safe.
• Nullability: cond must not be NULL.
• Error Conditions: None.
• Undefined Behavior: Passing NULL.
• Memory Allocation Expectations: None.
• Return-value Semantics: None (void).

Parameters

cond	The condition variable to broadcast. It must be a valid vl_condition that has been properly initialized.

vlConditionDelete()

void vlConditionDelete

(

vl_condition

cond

)

De-initializes and deletes a condition variable.

Contract

• Ownership: Releases ownership of the condition variable handle and its associated resources.
• Lifetime: The condition variable handle becomes invalid immediately after this call.
• Thread Safety: Safe to call from any thread, provided no thread is waiting on it.
• Nullability: Passing NULL results in undefined behavior (will attempt to destroy a null pointer).
• Error Conditions: None.
• Undefined Behavior: Passing NULL. Deleting a condition variable that still has threads waiting on it. Double deletion.
• Memory Allocation Expectations: Deallocates heap-allocated resources.
• Return-value Semantics: None (void).

Parameters

cond	The condition variable handle to delete.

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vlConditionNew()

vl_condition vlConditionNew

(

void

)

Creates and initializes a new condition variable.

Contract

• Ownership: The caller owns the returned vl_condition handle and is responsible for calling vlConditionDelete.
• Lifetime: The condition variable remains valid until vlConditionDelete.
• Thread Safety: This function is thread-safe.
• Nullability: Will attempt to return NULL if allocation fails, but the implementation may crash due to unhandled NULL in pthread_cond_init.
• Error Conditions: Crashes if heap allocation fails.
• Undefined Behavior: Allocation failure.
• Memory Allocation Expectations: Allocates condition variable metadata on the heap.
• Return-value Semantics: Returns an opaque handle to the new condition variable.

Returns

A vl_condition handle representing the newly created condition variable. The caller is responsible for deallocating the associated resources when they are no longer needed.

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vlConditionSignal()

void vlConditionSignal

(

vl_condition

cond

)

Signals a condition variable, waking up at least one thread waiting on it.

Contract

• Ownership: Unchanged.
• Lifetime: Unchanged.
• Thread Safety: Thread-safe.
• Nullability: cond must not be NULL.
• Error Conditions: None.
• Undefined Behavior: Passing NULL.
• Memory Allocation Expectations: None.
• Return-value Semantics: None (void).

Parameters

cond	The condition variable to signal.

vlConditionWait()

void vlConditionWait	(	vl_condition	cond,
		vl_mutex	mutex
	)

Waits on a condition variable.

This function causes the calling thread to block until the specified condition variable has been signaled. It atomically releases the provided mutex and suspends the thread execution until the condition is signaled. After being signaled, the mutex is reacquired by the calling thread before the function returns.

Contract

• Ownership: Unchanged. The calling thread must hold the mutex.
• Lifetime: Unchanged.
• Thread Safety: Thread-safe (blocking).
• Nullability: cond and mutex must not be NULL.
• Error Conditions: None.
• Undefined Behavior: Calling without holding the mutex. Spurious wakeups (caller should use a loop).
• Memory Allocation Expectations: None.
• Return-value Semantics: None (void).

Warning

The behavior is undefined if the mutex is not locked by the calling thread prior to calling this function.

Parameters

cond	The condition variable on which to wait.
mutex	The mutex associated with the condition variable. It must be locked by the calling thread before calling this function.

Note

This function relies on the proper behavior of the underlying condition and mutex mechanisms to ensure correct synchronization between threads.

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vlConditionWaitTimeout()

vl_bool_t vlConditionWaitTimeout	(	vl_condition	cond,
		vl_mutex	mutex,
		vl_ularge_t	millis
	)

Waits on a condition variable with a timeout.

Contract

• Ownership: Unchanged.
• Lifetime: Unchanged.
• Thread Safety: Thread-safe (blocking).
• Nullability: cond and mutex must not be NULL.
• Error Conditions: Returns VL_FALSE if the timeout expires.
• Undefined Behavior: Calling without holding the mutex.
• Memory Allocation Expectations: None.
• Return-value Semantics: Returns VL_TRUE if the condition was signaled, VL_FALSE on timeout or error.

Warning

The behavior is undefined if the mutex is not locked by the calling thread prior to calling this function.

Parameters

cond	The condition variable to wait on.
mutex	The mutex associated with the condition.
millis	The timeout period in milliseconds.

Returns

A boolean value that indicates whether the condition was signaled within the timeout. Returns true if the condition was signaled, or false if the timeout period elapsed without the condition being signaled.

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