timer.h

Overview

The timer.h file declares the timer APIs in C.

File to include: <ffrt/timer.h>

Library: libffrt.z.so

System capability: SystemCapability.Resourceschedule.Ffrt.Core

Since: 12

Related module: FFRT

Summary

Function

Name	Description
FFRT_C_API ffrt_timer_t ffrt_timer_start(ffrt_qos_t qos, uint64_t timeout, void* data, ffrt_timer_cb cb, bool repeat)	Starts the timer.
FFRT_C_API int ffrt_timer_stop(ffrt_qos_t qos, ffrt_timer_t handle)	Stops the timer.

Function Description

ffrt_timer_start()

FFRT_C_API ffrt_timer_t ffrt_timer_start(ffrt_qos_t qos, uint64_t timeout, void* data, ffrt_timer_cb cb, bool repeat)

Description

Starts the timer.

You are not advised to call the exit function in cb. Otherwise, undefined behavior may occur.

Since: 12

Parameters

Name	Description
ffrt_qos_t qos	QoS.
uint64_t timeout	Timeout, in milliseconds.
void* data	Pointer to the input parameter in the callback function invoked upon a timeout.
ffrt_timer_cb cb	Callback function invoked upon a timeout.
bool repeat	Whether to repeat the timer (not supported yet).

Returns

Type	Description
FFRT_C_API ffrt_timer_t	Returns the timer handle.

ffrt_timer_stop()

FFRT_C_API int ffrt_timer_stop(ffrt_qos_t qos, ffrt_timer_t handle)

Description

Stops the timer.

NOTE

• This is a blocking API and must not be used inside callback functions to prevent deadlocks or synchronization issues.

• If the callback corresponding to the passed handle is being executed, this function will wait for the callback to complete before resuming its own execution.

Since: 12

Parameters

Name	Description
ffrt_qos_t qos	QoS.
ffrt_timer_t handle	Handle to the timer.

Returns

Type	Description
FFRT_C_API int	Returns 0 if the timer is stopped successfully; returns -1 otherwise.