SDL 3.0
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#include <SDL3/SDL_stdinc.h>
#include <SDL3/SDL_error.h>
#include <SDL3/SDL_begin_code.h>
#include <SDL3/SDL_close_code.h>
Go to the source code of this file.
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_SECONDS_TO_NS(S) (((Uint64)(S)) * SDL_NS_PER_SECOND) |
#define | SDL_NS_TO_SECONDS(NS) ((NS) / SDL_NS_PER_SECOND) |
#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_TimerID |
typedef Uint32(* | SDL_TimerCallback) (void *userdata, SDL_TimerID timerID, Uint32 interval) |
typedef Uint64(* | SDL_NSTimerCallback) (void *userdata, SDL_TimerID timerID, Uint64 interval) |
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) |
void | SDL_DelayPrecise (Uint64 ns) |
SDL_TimerID | SDL_AddTimer (Uint32 interval, SDL_TimerCallback callback, void *userdata) |
SDL_TimerID | SDL_AddTimerNS (Uint64 interval, SDL_NSTimerCallback callback, void *userdata) |
bool | SDL_RemoveTimer (SDL_TimerID id) |
#define SDL_MS_PER_SECOND 1000 |
SDL provides time management functionality. It is useful for dealing with (usually) small durations of time.
This is not to be confused with calendar time management, which is provided by [CategoryTime](CategoryTime).
This category covers measuring time elapsed (SDL_GetTicks(), SDL_GetPerformanceCounter()), putting a thread to sleep for a certain amount of time (SDL_Delay(), SDL_DelayNS(), SDL_DelayPrecise()), and firing a callback function after a certain amount of time has elasped (SDL_AddTimer(), etc).
There are also useful macros to convert between time units, like SDL_SECONDS_TO_NS() and such. Number of milliseconds in a second.
This is always 1000.
Definition at line 62 of file SDL_timer.h.
#define SDL_MS_TO_NS | ( | MS | ) | (((Uint64)(MS)) * SDL_NS_PER_MS) |
Convert milliseconds to nanoseconds.
This only converts whole numbers, not fractional milliseconds.
MS | the number of milliseconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 141 of file SDL_timer.h.
#define SDL_NS_PER_MS 1000000 |
Number of nanoseconds in a millisecond.
This is always 1000000.
Definition at line 89 of file SDL_timer.h.
#define SDL_NS_PER_SECOND 1000000000LL |
Number of nanoseconds in a second.
This is always 1000000000.
Definition at line 80 of file SDL_timer.h.
#define SDL_NS_PER_US 1000 |
Number of nanoseconds in a microsecond.
This is always 1000.
Definition at line 98 of file SDL_timer.h.
#define SDL_NS_TO_MS | ( | NS | ) | ((NS) / SDL_NS_PER_MS) |
Convert nanoseconds to milliseconds.
This performs a division, so the results can be dramatically different if NS
is an integer or floating point value.
NS | the number of nanoseconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 156 of file SDL_timer.h.
#define SDL_NS_TO_SECONDS | ( | NS | ) | ((NS) / SDL_NS_PER_SECOND) |
Convert nanoseconds to seconds.
This performs a division, so the results can be dramatically different if NS
is an integer or floating point value.
NS | the number of nanoseconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 127 of file SDL_timer.h.
#define SDL_NS_TO_US | ( | NS | ) | ((NS) / SDL_NS_PER_US) |
Convert nanoseconds to microseconds.
This performs a division, so the results can be dramatically different if NS
is an integer or floating point value.
NS | the number of nanoseconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 185 of file SDL_timer.h.
#define SDL_SECONDS_TO_NS | ( | S | ) | (((Uint64)(S)) * SDL_NS_PER_SECOND) |
Convert seconds to nanoseconds.
This only converts whole numbers, not fractional seconds.
S | the number of seconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 112 of file SDL_timer.h.
#define SDL_US_PER_SECOND 1000000 |
Number of microseconds in a second.
This is always 1000000.
Definition at line 71 of file SDL_timer.h.
#define SDL_US_TO_NS | ( | US | ) | (((Uint64)(US)) * SDL_NS_PER_US) |
Convert microseconds to nanoseconds.
This only converts whole numbers, not fractional microseconds.
US | the number of microseconds to convert. |
\threadsafety It is safe to call this macro from any thread.
Definition at line 170 of file SDL_timer.h.
typedef Uint64(* SDL_NSTimerCallback) (void *userdata, SDL_TimerID timerID, Uint64 interval) |
Function prototype for the nanosecond timer callback function.
The callback function is passed the current timer interval and returns the next timer interval, in nanoseconds. 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 canceled and will be removed.
userdata | an arbitrary pointer provided by the app through SDL_AddTimer, for its own use. |
timerID | the current timer being processed. |
interval | the current callback time interval. |
\threadsafety SDL may call this callback at any time from a background thread; the application is responsible for locking resources the callback touches that need to be protected.
Definition at line 390 of file SDL_timer.h.
typedef Uint32(* SDL_TimerCallback) (void *userdata, SDL_TimerID timerID, Uint32 interval) |
Function prototype for the millisecond 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 canceled and will be removed.
userdata | an arbitrary pointer provided by the app through SDL_AddTimer, for its own use. |
timerID | the current timer being processed. |
interval | the current callback time interval. |
\threadsafety SDL may call this callback at any time from a background thread; the application is responsible for locking resources the callback touches that need to be protected.
Definition at line 328 of file SDL_timer.h.
typedef Uint32 SDL_TimerID |
Definition of the timer ID type.
Definition at line 302 of file SDL_timer.h.
SDL_TimerID SDL_AddTimer | ( | Uint32 | interval, |
SDL_TimerCallback | callback, | ||
void * | userdata | ||
) |
Call a callback function at a future time.
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 and will be removed.
The callback is run on a separate thread, and for short timeouts can potentially be called before this function returns.
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.
interval | the timer delay, in milliseconds, passed to callback . |
callback | the SDL_TimerCallback function to call when the specified interval elapses. |
userdata | a pointer that is passed to callback . |
\threadsafety It is safe to call this function from any thread.
SDL_TimerID SDL_AddTimerNS | ( | Uint64 | interval, |
SDL_NSTimerCallback | callback, | ||
void * | userdata | ||
) |
Call a callback function at a future time.
The callback function is passed the current timer interval and the user supplied parameter from the SDL_AddTimerNS() call and should return the next timer interval. If the value returned from the callback is 0, the timer is canceled and will be removed.
The callback is run on a separate thread, and for short timeouts can potentially be called before this function returns.
Timers take into account the amount of time it took to execute the callback. For example, if the callback took 250 ns to execute and returned 1000 (ns), the timer would only wait another 750 ns 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.
interval | the timer delay, in nanoseconds, passed to callback . |
callback | the SDL_TimerCallback function to call when the specified interval elapses. |
userdata | a pointer that is passed to callback . |
\threadsafety It is safe to call this function from any thread.
void SDL_Delay | ( | Uint32 | ms | ) |
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.
ms | the number of milliseconds to delay. |
\threadsafety It is safe to call this function from any thread.
void SDL_DelayNS | ( | Uint64 | ns | ) |
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.
ns | the number of nanoseconds to delay. |
\threadsafety It is safe to call this function from any thread.
void SDL_DelayPrecise | ( | Uint64 | ns | ) |
Wait a specified number of nanoseconds before returning.
This function waits a specified number of nanoseconds before returning. It will attempt to wait as close to the requested time as possible, busy waiting if necessary, but could return later due to OS scheduling.
ns | the number of nanoseconds to delay. |
\threadsafety It is safe to call this function from any thread.
Uint64 SDL_GetPerformanceCounter | ( | void | ) |
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().
\threadsafety It is safe to call this function from any thread.
Uint64 SDL_GetPerformanceFrequency | ( | void | ) |
Get the count per second of the high resolution counter.
\threadsafety It is safe to call this function from any thread.
Uint64 SDL_GetTicks | ( | void | ) |
Get the number of milliseconds since SDL library initialization.
\threadsafety It is safe to call this function from any thread.
Uint64 SDL_GetTicksNS | ( | void | ) |
Get the number of nanoseconds since SDL library initialization.
\threadsafety It is safe to call this function from any thread.
bool SDL_RemoveTimer | ( | SDL_TimerID | id | ) |
Remove a timer created with SDL_AddTimer().
id | the ID of the timer to remove. |
\threadsafety It is safe to call this function from any thread.