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Sync SDL3 wiki -> header
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@@ -65,21 +65,20 @@ extern "C" {
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/**
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/**
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* An atomic spinlock.
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* An atomic spinlock.
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*
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*
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* The atomic locks are efficient spinlocks using CPU instructions,
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* The atomic locks are efficient spinlocks using CPU instructions, but are
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* but are vulnerable to starvation and can spin forever if a thread
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* vulnerable to starvation and can spin forever if a thread holding a lock
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* holding a lock has been terminated. For this reason you should
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* has been terminated. For this reason you should minimize the code executed
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* minimize the code executed inside an atomic lock and never do
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* inside an atomic lock and never do expensive things like API or system
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* expensive things like API or system calls while holding them.
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* calls while holding them.
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*
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*
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* They are also vulnerable to starvation if the thread holding
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* They are also vulnerable to starvation if the thread holding the lock is
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* the lock is lower priority than other threads and doesn't get
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* lower priority than other threads and doesn't get scheduled. In general you
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* scheduled. In general you should use mutexes instead, since
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* should use mutexes instead, since they have better performance and
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* they have better performance and contention behavior.
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* contention behavior.
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*
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*
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* The atomic locks are not safe to lock recursively.
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* The atomic locks are not safe to lock recursively.
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*
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*
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* Porting Note:
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* Porting Note: The spin lock functions and type are required and can not be
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* The spin lock functions and type are required and can not be
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* emulated because they are used in the atomic emulation code.
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* emulated because they are used in the atomic emulation code.
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*/
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*/
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typedef int SDL_SpinLock;
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typedef int SDL_SpinLock;
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@@ -264,11 +263,12 @@ typedef void (*SDL_KernelMemoryBarrierFunc)();
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/* "REP NOP" is PAUSE, coded for tools that don't know it by that name. */
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/* "REP NOP" is PAUSE, coded for tools that don't know it by that name. */
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#ifdef SDL_WIKI_DOCUMENTATION_SECTION
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#ifdef SDL_WIKI_DOCUMENTATION_SECTION
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/**
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/**
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* A macro to insert a CPU-specific "pause" instruction into the program.
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* A macro to insert a CPU-specific "pause" instruction into the program.
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*
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*
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* This can be useful in busy-wait loops, as it serves as a hint to the CPU
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* This can be useful in busy-wait loops, as it serves as a hint to the CPU as
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* as to the program's intent; some CPUs can use this to do more efficient
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* to the program's intent; some CPUs can use this to do more efficient
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* processing. On some platforms, this doesn't do anything, so using this
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* processing. On some platforms, this doesn't do anything, so using this
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* macro might just be a harmless no-op.
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* macro might just be a harmless no-op.
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*
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*
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@@ -309,16 +309,16 @@ typedef void (*SDL_KernelMemoryBarrierFunc)();
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* all other threads, regardless of the CPU it is running on, will see that
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* all other threads, regardless of the CPU it is running on, will see that
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* value when retrieved with SDL_AtomicGet, regardless of CPU caches, etc.
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* value when retrieved with SDL_AtomicGet, regardless of CPU caches, etc.
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*
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*
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* This is also useful for atomic compare-and-swap operations: a thread
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* This is also useful for atomic compare-and-swap operations: a thread can
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* can change the value as long as its current value matches expectations.
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* change the value as long as its current value matches expectations. When
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* When done in a loop, one can guarantee data consistency across threads
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* done in a loop, one can guarantee data consistency across threads without a
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* without a lock (but the usual warnings apply: if you don't know what
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* lock (but the usual warnings apply: if you don't know what you're doing, or
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* you're doing, or you don't do it carefully, you can confidently cause
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* you don't do it carefully, you can confidently cause any number of
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* any number of disasters with this, so in most cases, you _should_
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* disasters with this, so in most cases, you _should_ use a mutex instead of
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* use a mutex instead of this!).
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* this!).
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*
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*
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* This is a struct so people don't accidentally use numeric operations on
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* This is a struct so people don't accidentally use numeric operations on it
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* it directly. You have to use SDL_Atomic* functions.
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* directly. You have to use SDL_Atomic* functions.
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*
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*
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* \since This struct is available since SDL 3.0.0.
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* \since This struct is available since SDL 3.0.0.
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*
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*
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