SDL 3.0
SDL_timer.h File Reference

Header for the SDL time management routines. More...

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Macros

#define SDL_MS_PER_SECOND   1000
 
#define SDL_US_PER_SECOND   1000000
 
#define SDL_NS_PER_SECOND   1000000000LL
 
#define SDL_NS_PER_MS   1000000
 
#define SDL_NS_PER_US   1000
 
#define SDL_MS_TO_NS(MS)   (((Uint64)(MS)) * SDL_NS_PER_MS)
 
#define SDL_NS_TO_MS(NS)   ((NS) / SDL_NS_PER_MS)
 
#define SDL_US_TO_NS(US)   (((Uint64)(US)) * SDL_NS_PER_US)
 
#define SDL_NS_TO_US(NS)   ((NS) / SDL_NS_PER_US)
 

Typedefs

typedef Uint32(* SDL_TimerCallback) (Uint32 interval, void *param)
 
typedef int SDL_TimerID
 

Functions

Uint64 SDL_GetTicks (void)
 
Uint64 SDL_GetTicksNS (void)
 
Uint64 SDL_GetPerformanceCounter (void)
 
Uint64 SDL_GetPerformanceFrequency (void)
 
void SDL_Delay (Uint32 ms)
 
void SDL_DelayNS (Uint64 ns)
 
SDL_TimerID SDL_AddTimer (Uint32 interval, SDL_TimerCallback callback, void *param)
 
SDL_bool SDL_RemoveTimer (SDL_TimerID id)
 

Detailed Description

Header for the SDL time management routines.

Definition in file SDL_timer.h.

Macro Definition Documentation

◆ SDL_MS_PER_SECOND

#define SDL_MS_PER_SECOND   1000

SDL time constants

Definition at line 43 of file SDL_timer.h.

◆ SDL_MS_TO_NS

#define SDL_MS_TO_NS (   MS)    (((Uint64)(MS)) * SDL_NS_PER_MS)

Definition at line 48 of file SDL_timer.h.

◆ SDL_NS_PER_MS

#define SDL_NS_PER_MS   1000000

Definition at line 46 of file SDL_timer.h.

◆ SDL_NS_PER_SECOND

#define SDL_NS_PER_SECOND   1000000000LL

Definition at line 45 of file SDL_timer.h.

◆ SDL_NS_PER_US

#define SDL_NS_PER_US   1000

Definition at line 47 of file SDL_timer.h.

◆ SDL_NS_TO_MS

#define SDL_NS_TO_MS (   NS)    ((NS) / SDL_NS_PER_MS)

Definition at line 49 of file SDL_timer.h.

◆ SDL_NS_TO_US

#define SDL_NS_TO_US (   NS)    ((NS) / SDL_NS_PER_US)

Definition at line 51 of file SDL_timer.h.

◆ SDL_US_PER_SECOND

#define SDL_US_PER_SECOND   1000000

Definition at line 44 of file SDL_timer.h.

◆ SDL_US_TO_NS

#define SDL_US_TO_NS (   US)    (((Uint64)(US)) * SDL_NS_PER_US)

Definition at line 50 of file SDL_timer.h.

Typedef Documentation

◆ SDL_TimerCallback

typedef Uint32(* SDL_TimerCallback) (Uint32 interval, void *param)

Function prototype for the timer callback function.

The callback function is passed the current timer interval and returns the next timer interval, in milliseconds. If the returned value is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled. If the callback returns 0, the periodic alarm is cancelled.

Definition at line 135 of file SDL_timer.h.

◆ SDL_TimerID

typedef int SDL_TimerID

Definition of the timer ID type.

Definition at line 140 of file SDL_timer.h.

Function Documentation

◆ SDL_AddTimer()

SDL_TimerID SDL_AddTimer ( Uint32  interval,
SDL_TimerCallback  callback,
void *  param 
)
extern

Call a callback function at a future time.

If you use this function, you must pass SDL_INIT_TIMER to SDL_Init().

The callback function is passed the current timer interval and the user supplied parameter from the SDL_AddTimer() call and should return the next timer interval. If the value returned from the callback is 0, the timer is canceled.

The callback is run on a separate thread.

Timers take into account the amount of time it took to execute the callback. For example, if the callback took 250 ms to execute and returned 1000 (ms), the timer would only wait another 750 ms before its next iteration.

Timing may be inexact due to OS scheduling. Be sure to note the current time with SDL_GetTicksNS() or SDL_GetPerformanceCounter() in case your callback needs to adjust for variances.

Parameters
intervalthe timer delay, in milliseconds, passed to callback
callbackthe SDL_TimerCallback function to call when the specified interval elapses
parama pointer that is passed to callback
Returns
a timer ID or 0 if an error occurs; call SDL_GetError() for more information.
Since
This function is available since SDL 3.0.0.
See also
SDL_RemoveTimer

◆ SDL_Delay()

void SDL_Delay ( Uint32  ms)
extern

Wait a specified number of milliseconds before returning.

This function waits a specified number of milliseconds before returning. It waits at least the specified time, but possibly longer due to OS scheduling.

Parameters
msthe number of milliseconds to delay
Since
This function is available since SDL 3.0.0.

◆ SDL_DelayNS()

void SDL_DelayNS ( Uint64  ns)
extern

Wait a specified number of nanoseconds before returning.

This function waits a specified number of nanoseconds before returning. It waits at least the specified time, but possibly longer due to OS scheduling.

Parameters
nsthe number of nanoseconds to delay
Since
This function is available since SDL 3.0.0.

◆ SDL_GetPerformanceCounter()

Uint64 SDL_GetPerformanceCounter ( void  )
extern

Get the current value of the high resolution counter.

This function is typically used for profiling.

The counter values are only meaningful relative to each other. Differences between values can be converted to times by using SDL_GetPerformanceFrequency().

Returns
the current counter value.
Since
This function is available since SDL 3.0.0.
See also
SDL_GetPerformanceFrequency

◆ SDL_GetPerformanceFrequency()

Uint64 SDL_GetPerformanceFrequency ( void  )
extern

Get the count per second of the high resolution counter.

Returns
a platform-specific count per second.
Since
This function is available since SDL 3.0.0.
See also
SDL_GetPerformanceCounter

◆ SDL_GetTicks()

Uint64 SDL_GetTicks ( void  )
extern

Get the number of milliseconds since SDL library initialization.

Returns
an unsigned 64-bit value representing the number of milliseconds since the SDL library initialized.
Since
This function is available since SDL 3.0.0.

◆ SDL_GetTicksNS()

Uint64 SDL_GetTicksNS ( void  )
extern

Get the number of nanoseconds since SDL library initialization.

Returns
an unsigned 64-bit value representing the number of nanoseconds since the SDL library initialized.
Since
This function is available since SDL 3.0.0.

◆ SDL_RemoveTimer()

SDL_bool SDL_RemoveTimer ( SDL_TimerID  id)
extern

Remove a timer created with SDL_AddTimer().

Parameters
idthe ID of the timer to remove
Returns
SDL_TRUE if the timer is removed or SDL_FALSE if the timer wasn't found.
Since
This function is available since SDL 3.0.0.
See also
SDL_AddTimer