All SDL programs need to initialize the library before starting to work with it.
More...
|
#define | SDL3PP_APPCLASS_LOG_PRIORITY LOG_PRIORITY_CRITICAL |
| The default log priority for app class.
|
|
|
using | SDL::AppArgs = std::span< char const *const > |
| Represents application parameters.
|
|
|
void | SDL::InitSubSystem (InitFlags flags) |
| Initialize the SDL library.
|
|
template<class FLAG0 , class FLAG1 , class... FLAGS> |
void | SDL::InitSubSystem (FLAG0 flag0, FLAG1 flag1, FLAGS... flags) |
| Initialize the SDL library.
|
|
template<class FLAG , class... FLAGS> |
void | SDL::InitSubSystem (FLAG flag0, FLAG flag1, FLAGS... flags) |
| Initialize the SDL library.
|
|
void | SDL::QuitSubSystem (InitFlags flags) |
| Shut down specific SDL subsystems.
|
|
template<class FLAG0 , class FLAG1 , class... FLAGS> |
void | SDL::QuitSubSystem (FLAG0 flag0, FLAG1 flag1, FLAGS... flags) |
| Shut down specific SDL subsystems.
|
|
template<class FLAG , class... FLAGS> |
void | SDL::QuitSubSystem (FLAG flag0, FLAG flag1, FLAGS... flags) |
| Shut down specific SDL subsystems.
|
|
bool | SDL::WasInit (InitFlags flags) |
| Check if all of the specified subsystems which are currently initialized.
|
|
template<class FLAG0 , class FLAG1 , class... FLAGS> |
bool | SDL::WasInit (FLAG0 flag0, FLAG1 flag1, FLAGS... flags) |
| Check if all of the specified subsystems which are currently initialized.
|
|
template<class FLAG , class... FLAGS> |
bool | SDL::WasInit (FLAG flag0, FLAG flag1, FLAGS... flags) |
| Check if all of the specified subsystems which are currently initialized.
|
|
void | SDL::Quit () |
| Clean up all initialized subsystems.
|
|
bool | SDL::IsMainThread () |
| Return whether this is the main thread.
|
|
void | SDL::RunOnMainThread (MainThreadCallback callback, void *userdata, bool wait_complete) |
| Call a function on the main thread during event processing.
|
|
void | SDL::RunOnMainThread (MainThreadCB callback, bool wait_complete) |
| Call a function on the main thread during event processing.
|
|
void | SDL::SetAppMetadata (StringParam appname, StringParam appversion, StringParam appidentifier) |
| Specify basic metadata about your app.
|
|
void | SDL::SetAppMetadataProperty (StringParam name, StringParam value) |
| Specify metadata about your app through a set of properties.
|
|
const char * | SDL::GetAppMetadataProperty (StringParam name) |
| Get metadata about your app.
|
|
template<HasIterateFunction T> |
AppResult | SDL::IterateClass (T *state) |
| Iterate the state.
|
|
template<class T > |
AppResult | SDL::DefaultEventClass (T *state, const SDL_Event &event) |
| Default handle by finishing if QUIT is requested.
|
|
template<class T > |
void | SDL::DefaultClassDestroy (T *state) |
| Destroy state with delete;.
|
|
|
App result for Main callback
|
using | SDL::AppResult = SDL_AppResult |
| Return values for optional main callbacks.
|
|
constexpr AppResult | SDL::APP_CONTINUE = SDL_APP_CONTINUE |
| Value that requests that the app continue from the main callbacks.
|
|
constexpr AppResult | SDL::APP_SUCCESS = SDL_APP_SUCCESS |
| Value that requests termination with success from the main callbacks.
|
|
constexpr AppResult | SDL::APP_FAILURE = SDL_APP_FAILURE |
| Value that requests termination with error from the main callbacks.
|
|
Almost everything can simply call SDL_Init() near startup, with a handful of flags to specify subsystems to touch. These are here to make sure SDL does not even attempt to touch low-level pieces of the operating system that you don't intend to use. For example, you might be using SDL for video and input but chose an external library for audio, and in this case you would just need to leave off the SDL_INIT_AUDIO
flag to make sure that external library has complete control.
Most apps, when terminating, should call SDL_Quit(). This will clean up (nearly) everything that SDL might have allocated, and crucially, it'll make sure that the display's resolution is back to what the user expects if you had previously changed it for your game.
SDL3 apps are strongly encouraged to call SDL_SetAppMetadata() at startup to fill in details about the program. This is completely optional, but it helps in small ways (we can provide an About dialog box for the macOS menu, we can name the app in the system's audio mixer, etc). Those that want to provide a lot of information should look at the more-detailed SDL_SetAppMetadataProperty().
◆ AppEvent_func
These are used by EnterAppMainCallbacks. This mechanism operates behind the scenes for apps using the optional main callbacks. Apps that want to use this should just implement SDL_AppEvent directly.
- Parameters
-
appstate | an optional pointer, provided by the app in SDL_AppInit. |
event | the new event for the app to examine. |
- Returns
- APP_FAILURE to terminate with an error, APP_SUCCESS to terminate with success, APP_CONTINUE to continue.
- Since
- This datatype is available since SDL 3.2.0.
◆ AppInit_func
These are used by EnterAppMainCallbacks. This mechanism operates behind the scenes for apps using the optional main callbacks. Apps that want to use this should just implement SDL_AppInit directly.
- Parameters
-
appstate | a place where the app can optionally store a pointer for future use. |
argc | the standard ANSI C main's argc; number of elements in argv . |
argv | the standard ANSI C main's argv; array of command line arguments. |
- Returns
- APP_FAILURE to terminate with an error, APP_SUCCESS to terminate with success, APP_CONTINUE to continue.
- Since
- This datatype is available since SDL 3.2.0.
◆ AppIterate_func
These are used by EnterAppMainCallbacks. This mechanism operates behind the scenes for apps using the optional main callbacks. Apps that want to use this should just implement SDL_AppIterate directly.
- Parameters
-
appstate | an optional pointer, provided by the app in SDL_AppInit. |
- Returns
- APP_FAILURE to terminate with an error, APP_SUCCESS to terminate with success, APP_CONTINUE to continue.
- Since
- This datatype is available since SDL 3.2.0.
◆ AppQuit_func
These are used by EnterAppMainCallbacks. This mechanism operates behind the scenes for apps using the optional main callbacks. Apps that want to use this should just implement SDL_AppEvent directly.
- Parameters
-
appstate | an optional pointer, provided by the app in SDL_AppInit. |
result | the result code that terminated the app (success or failure). |
- Since
- This datatype is available since SDL 3.2.0.
◆ AppResult
Returning APP_SUCCESS or APP_FAILURE from SDL_AppInit, SDL_AppEvent, or SDL_AppIterate will terminate the program and report success/failure to the operating system. What that means is platform-dependent. On Unix, for example, on success, the process error code will be zero, and on failure it will be 1. This interface doesn't allow you to return specific exit codes, just whether there was an error generally or not.
Returning APP_CONTINUE from these functions will let the app continue to run.
See Main callbacks in SDL3 for complete details.
- Since
- This enum is available since SDL 3.2.0.
◆ MainThreadCallback
- Parameters
-
userdata | an app-controlled pointer that is passed to the callback. |
- Since
- This datatype is available since SDL 3.2.0.
- See also
- RunOnMainThread
◆ MainThreadCB
- See also
- PropertiesRef.MainThreadCallback
-
result-callback
- Category:
- Result callback
◆ DefaultClassDestroy()
template<class T >
void SDL::DefaultClassDestroy |
( |
T * |
state | ) |
|
|
inline |
- Template Parameters
-
- Parameters
-
◆ DefaultCreateClass()
If possible, pass the args to constructor, otherwise expects a default ctor;
- Template Parameters
-
- Parameters
-
state | the state to initialize |
args | the program arguments |
- Returns
- the app status
◆ DefaultEventClass()
template<class T >
AppResult SDL::DefaultEventClass |
( |
T * |
state, |
|
|
const SDL_Event & |
event |
|
) |
| |
|
inline |
- Template Parameters
-
- Parameters
-
state | the state |
event | the event |
- Returns
- APP_SUCCESS if event is QUIT_EVENT, APP_CONTINUE otherwise,
◆ EventClass()
template<class T >
AppResult SDL::EventClass |
( |
T * |
state, |
|
|
const SDL_Event & |
event |
|
) |
| |
|
inline |
- Template Parameters
-
- Parameters
-
state | the state |
event | the event to handle |
- Returns
- the app status
◆ GetAppMetadataProperty()
const char * SDL::GetAppMetadataProperty |
( |
StringParam |
name | ) |
|
|
inline |
This returns metadata previously set using SetAppMetadata() or SetAppMetadataProperty(). See SetAppMetadataProperty() for the list of available properties and their meanings.
- Parameters
-
name | the name of the metadata property to get. |
- Returns
- the current value of the metadata property, or the default if it is not set, nullptr for properties with no default.
- Thread safety:
- It is safe to call this function from any thread, although the string returned is not protected and could potentially be freed if you call SetAppMetadataProperty() to set that property from another thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- SetAppMetadata
-
SetAppMetadataProperty
◆ InitClass()
This will call T::Init() if available, otherwise it delegates to DefaultCreateClass().
- Template Parameters
-
- Parameters
-
state | the state to initialize |
args | the program arguments |
- Returns
- the app status
◆ InitSubSystem() [1/3]
template<class FLAG , class... FLAGS>
void SDL::InitSubSystem |
( |
FLAG |
flag0, |
|
|
FLAG |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
The class Init is probably what you are looking for, as it automatically handles de-initialization.
The file I/O (for example: IOStream) and threading (CreateThread) subsystems are initialized by default. Message boxes (ShowSimpleMessageBox) also attempt to work without initializing the video subsystem, in hopes of being useful in showing an error dialog when Init fails. You must specifically initialize other subsystems if you use them in your application.
Logging (such as Log) works without initialization, too.
flags
may be any of the following OR'd together:
INIT_AUDIO
: audio subsystem; automatically initializes the events subsystem
INIT_VIDEO
: video subsystem; automatically initializes the events subsystem, should be initialized on the main thread.
INIT_JOYSTICK
: joystick subsystem; automatically initializes the events subsystem
INIT_HAPTIC
: haptic (force feedback) subsystem
INIT_GAMEPAD
: gamepad subsystem; automatically initializes the joystick subsystem
INIT_EVENTS
: events subsystem
INIT_SENSOR
: sensor subsystem; automatically initializes the events subsystem
INIT_CAMERA
: camera subsystem; automatically initializes the events subsystem
INIT_TTF
: ttf satellite library subsystem; automatically initializes the events subsystem
Subsystem initialization is ref-counted, you must call QuitSubSystem() for each InitSubSystem() to correctly shutdown a subsystem manually (or call Quit() to force shutdown). If a subsystem is already loaded then this call will increase the ref-count and return.
Consider reporting some basic metadata about your application before calling Init, using either SetAppMetadata() or SetAppMetadataProperty().
- Template Parameters
-
- Parameters
-
flag0 | subsystem initialization flags. |
flag1 | subsystem initialization flags. |
flags | subsystem initialization flags. |
- Exceptions
-
- Since
- This function is available since SDL 3.2.0.
- See also
- SetAppMetadata()
-
SetAppMetadataProperty()
-
InitSubSystem()
-
Quit()
-
SetMainReady()
-
WasInit()
◆ InitSubSystem() [2/3]
template<class FLAG0 , class FLAG1 , class... FLAGS>
void SDL::InitSubSystem |
( |
FLAG0 |
flag0, |
|
|
FLAG1 |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
The class Init is probably what you are looking for, as it automatically handles de-initialization.
The file I/O (for example: IOStream) and threading (CreateThread) subsystems are initialized by default. Message boxes (ShowSimpleMessageBox) also attempt to work without initializing the video subsystem, in hopes of being useful in showing an error dialog when Init fails. You must specifically initialize other subsystems if you use them in your application.
Logging (such as Log) works without initialization, too.
flags
may be any of the following OR'd together:
INIT_AUDIO
: audio subsystem; automatically initializes the events subsystem
INIT_VIDEO
: video subsystem; automatically initializes the events subsystem, should be initialized on the main thread.
INIT_JOYSTICK
: joystick subsystem; automatically initializes the events subsystem
INIT_HAPTIC
: haptic (force feedback) subsystem
INIT_GAMEPAD
: gamepad subsystem; automatically initializes the joystick subsystem
INIT_EVENTS
: events subsystem
INIT_SENSOR
: sensor subsystem; automatically initializes the events subsystem
INIT_CAMERA
: camera subsystem; automatically initializes the events subsystem
INIT_TTF
: ttf satellite library subsystem; automatically initializes the events subsystem
Subsystem initialization is ref-counted, you must call QuitSubSystem() for each InitSubSystem() to correctly shutdown a subsystem manually (or call Quit() to force shutdown). If a subsystem is already loaded then this call will increase the ref-count and return.
Consider reporting some basic metadata about your application before calling Init, using either SetAppMetadata() or SetAppMetadataProperty().
- Template Parameters
-
- Parameters
-
flag0 | subsystem initialization flags. |
flag1 | subsystem initialization flags. |
flags | subsystem initialization flags. |
- Exceptions
-
- Since
- This function is available since SDL 3.2.0.
- See also
- SetAppMetadata()
-
SetAppMetadataProperty()
-
InitSubSystem()
-
Quit()
-
SetMainReady()
-
WasInit()
◆ InitSubSystem() [3/3]
The class Init is probably what you are looking for, as it automatically handles de-initialization.
The file I/O (for example: IOStreamBase.IOStreamBase) and threading (ThreadBase.ThreadBase) subsystems are initialized by default. Message boxes (ShowSimpleMessageBox) also attempt to work without initializing the video subsystem, in hopes of being useful in showing an error dialog when Init fails. You must specifically initialize other subsystems if you use them in your application.
Logging (such as Log) works without initialization, too.
flags
may be any of the following OR'd together:
INIT_AUDIO
: audio subsystem; automatically initializes the events subsystem
INIT_VIDEO
: video subsystem; automatically initializes the events subsystem, should be initialized on the main thread.
INIT_JOYSTICK
: joystick subsystem; automatically initializes the events subsystem
INIT_HAPTIC
: haptic (force feedback) subsystem
INIT_GAMEPAD
: gamepad subsystem; automatically initializes the joystick subsystem
INIT_EVENTS
: events subsystem
INIT_SENSOR
: sensor subsystem; automatically initializes the events subsystem
INIT_CAMERA
: camera subsystem; automatically initializes the events subsystem
INIT_TTF
: ttf satellite library subsystem; automatically initializes the events subsystem
Subsystem initialization is ref-counted, you must call QuitSubSystem() for each SDL_InitSubSystem() to correctly shutdown a subsystem manually (or call Quit() to force shutdown). If a subsystem is already loaded then this call will increase the ref-count and return.
Consider reporting some basic metadata about your application before calling InitSubSystem, using either SetAppMetadata() or SetAppMetadataProperty().
- Parameters
-
flags | subsystem initialization flags. |
- Exceptions
-
- Since
- This function is available since SDL 3.2.0.
- See also
- SetAppMetadata
-
SetAppMetadataProperty
-
Quit
-
SetMainReady
-
WasInit
◆ IsMainThread()
bool SDL::IsMainThread |
( |
| ) |
|
|
inline |
On Apple platforms, the main thread is the thread that runs your program's main() entry point. On other platforms, the main thread is the one that calls InitSubSystem(INIT_VIDEO), which should usually be the one that runs your program's main() entry point. If you are using the main callbacks, SDL_AppInit(), SDL_AppIterate(), and SDL_AppQuit() are all called on the main thread.
- Returns
- true if this thread is the main thread, or false otherwise.
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- RunOnMainThread
◆ IterateClass()
template<HasIterateFunction T>
- Template Parameters
-
- Parameters
-
- Returns
- the app status
◆ Quit()
You should call this function even if you have already shutdown each initialized subsystem with QuitSubSystem(). It is safe to call this function even in the case of errors in initialization.
You can use this function with atexit() to ensure that it is run when your application is shutdown, but it is not wise to do this from a library or other dynamically loaded code.
- Since
- This function is available since SDL 3.2.0.
- See also
- InitSubSystem
-
QuitSubSystem
◆ QuitClass()
template<class T >
void SDL::QuitClass |
( |
T * |
state, |
|
|
AppResult |
result |
|
) |
| |
|
inline |
This is responsible to destroy and deallocate the state. It tries to call T::Quit() if available and delegates to it the duty of deleting. Otherwise it calls delete directly.
- Template Parameters
-
- Parameters
-
state | the state to destroy. |
result | the app result. |
◆ QuitSubSystem() [1/3]
template<class FLAG , class... FLAGS>
void SDL::QuitSubSystem |
( |
FLAG |
flag0, |
|
|
FLAG |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
You still need to call Quit() even if you close all open subsystems with QuitSubSystem().
- Template Parameters
-
- Parameters
-
flag0 | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
flag1 | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
flags | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
◆ QuitSubSystem() [2/3]
template<class FLAG0 , class FLAG1 , class... FLAGS>
void SDL::QuitSubSystem |
( |
FLAG0 |
flag0, |
|
|
FLAG1 |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
You still need to call Quit() even if you close all open subsystems with QuitSubSystem().
- Template Parameters
-
- Parameters
-
flag0 | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
flag1 | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
flags | any of the flags used by Init(); see InitFlags and InitFlagsExtra for details. |
◆ QuitSubSystem() [3/3]
◆ RunOnMainThread() [1/2]
void SDL::RunOnMainThread |
( |
MainThreadCallback |
callback, |
|
|
void * |
userdata, |
|
|
bool |
wait_complete |
|
) |
| |
|
inline |
If this is called on the main thread, the callback is executed immediately. If this is called on another thread, this callback is queued for execution on the main thread during event processing.
Be careful of deadlocks when using this functionality. You should not have the main thread wait for the current thread while this function is being called with wait_complete
true.
- Parameters
-
callback | the callback to call on the main thread. |
userdata | a pointer that is passed to callback . |
wait_complete | true to wait for the callback to complete, false to return immediately. |
- Exceptions
-
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- IsMainThread
◆ RunOnMainThread() [2/2]
void SDL::RunOnMainThread |
( |
MainThreadCB |
callback, |
|
|
bool |
wait_complete |
|
) |
| |
|
inline |
If this is called on the main thread, the callback is executed immediately. If this is called on another thread, this callback is queued for execution on the main thread during event processing.
Be careful of deadlocks when using this functionality. You should not have the main thread wait for the current thread while this function is being called with wait_complete
true.
- Parameters
-
callback | the callback to call on the main thread. |
wait_complete | true to wait for the callback to complete, false to return immediately. |
- Exceptions
-
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- IsMainThread()
-
result-callback
- Category:
- Result callback
◆ SetAppMetadata()
You can optionally provide metadata about your app to SDL. This is not required, but strongly encouraged.
There are several locations where SDL can make use of metadata (an "About" box in the macOS menu bar, the name of the app can be shown on some audio mixers, etc). Any piece of metadata can be left as nullptr, if a specific detail doesn't make sense for the app.
This function should be called as early as possible, before InitSubSystem. Multiple calls to this function are allowed, but various state might not change once it has been set up with a previous call to this function.
Passing a nullptr removes any previous metadata.
This is a simplified interface for the most important information. You can supply significantly more detailed metadata with SetAppMetadataProperty().
- Parameters
-
appname | The name of the application ("My Game 2: Bad Guy's
Revenge!"). |
appversion | The version of the application ("1.0.0beta5" or a git hash, or whatever makes sense). |
appidentifier | A unique string in reverse-domain format that identifies this app ("com.example.mygame2"). |
- Exceptions
-
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- SetAppMetadataProperty
◆ SetAppMetadataProperty()
You can optionally provide metadata about your app to SDL. This is not required, but strongly encouraged.
There are several locations where SDL can make use of metadata (an "About" box in the macOS menu bar, the name of the app can be shown on some audio mixers, etc). Any piece of metadata can be left out, if a specific detail doesn't make sense for the app.
This function should be called as early as possible, before InitSubSystem. Multiple calls to this function are allowed, but various state might not change once it has been set up with a previous call to this function.
Once set, this metadata can be read using GetAppMetadataProperty().
These are the supported properties:
prop::appMetaData.NAME_STRING
: The human-readable name of the application, like "My Game 2: Bad Guy's Revenge!". This will show up anywhere the OS shows the name of the application separately from window titles, such as volume control applets, etc. This defaults to "SDL
Application".
prop::appMetaData.VERSION_STRING
: The version of the app that is running; there are no rules on format, so "1.0.3beta2" and "April 22nd,
2024" and a git hash are all valid options. This has no default.
prop::appMetaData.IDENTIFIER_STRING
: A unique string that identifies this app. This must be in reverse-domain format, like "com.example.mygame2". This string is used by desktop compositors to identify and group windows together, as well as match applications with associated desktop settings and icons. If you plan to package your application in a container such as Flatpak, the app ID should match the name of your Flatpak container as well. This has no default.
prop::appMetaData.CREATOR_STRING
: The human-readable name of the creator/developer/maker of this app, like "MojoWorkshop, LLC"
prop::appMetaData.COPYRIGHT_STRING
: The human-readable copyright notice, like "Copyright (c) 2024 MojoWorkshop, LLC" or whatnot. Keep this to one line, don't paste a copy of a whole software license in here. This has no default.
prop::appMetaData.URL_STRING
: A URL to the app on the web. Maybe a product page, or a storefront, or even a GitHub repository, for user's further information This has no default.
prop::appMetaData.TYPE_STRING
: The type of application this is. Currently this string can be "game" for a video game, "mediaplayer" for a media player, or generically "application" if nothing else applies. Future versions of SDL might add new types. This defaults to "application".
- Parameters
-
name | the name of the metadata property to set. |
value | the value of the property, or nullptr to remove that property. |
- Exceptions
-
- Thread safety:
- It is safe to call this function from any thread.
- Since
- This function is available since SDL 3.2.0.
- See also
- GetAppMetadataProperty
-
SetAppMetadata
◆ WasInit() [1/3]
template<class FLAG , class... FLAGS>
bool SDL::WasInit |
( |
FLAG |
flag0, |
|
|
FLAG |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
- Template Parameters
-
- Parameters
-
flag0 | flag to check |
flag1 | flag to check |
flags | flag to check |
- Returns
- true if all subsystems are currently initialized
◆ WasInit() [2/3]
template<class FLAG0 , class FLAG1 , class... FLAGS>
bool SDL::WasInit |
( |
FLAG0 |
flag0, |
|
|
FLAG1 |
flag1, |
|
|
FLAGS... |
flags |
|
) |
| |
|
inline |
- Template Parameters
-
- Parameters
-
flag0 | flag to check |
flag1 | flag to check |
flags | flag to check |
- Returns
- true if all subsystems are currently initialized
◆ WasInit() [3/3]
- Parameters
-
flags | any of the flags used by InitSubSystem(); see InitSubSystem for details. |
- Returns
- true if all subsystems are currently initialized
- Since
- This function is available since SDL 3.2.0.
- See also
- InitSubSystem
-
SDL_InitSubSystem