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pixhawk's avatar
Fixed QMapControl, added SDL
6d91ce03
 
pixhawk committed
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<HTML
><HEAD
><TITLE
>Multi-threaded Programming</TITLE
><META
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>SDL Library Documentation</TH
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><HR
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><DIV
CLASS="CHAPTER"
><H1
><A
NAME="THREAD"
></A
>Chapter 12. Multi-threaded Programming</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlcreatethread.html"
>SDL_CreateThread</A
>&nbsp;--&nbsp;Creates a new thread of execution that shares its parent's properties.</DT
><DT
><A
HREF="sdlthreadid.html"
>SDL_ThreadID</A
>&nbsp;--&nbsp;Get the 32-bit thread identifier for the current thread.</DT
><DT
><A
HREF="sdlgetthreadid.html"
>SDL_GetThreadID</A
>&nbsp;--&nbsp;Get the SDL thread ID of a SDL_Thread</DT
><DT
><A
HREF="sdlwaitthread.html"
>SDL_WaitThread</A
>&nbsp;--&nbsp;Wait for a thread to finish.</DT
><DT
><A
HREF="sdlkillthread.html"
>SDL_KillThread</A
>&nbsp;--&nbsp;Gracelessly terminates the thread.</DT
><DT
><A
HREF="sdlcreatemutex.html"
>SDL_CreateMutex</A
>&nbsp;--&nbsp;Create a mutex</DT
><DT
><A
HREF="sdldestroymutex.html"
>SDL_DestroyMutex</A
>&nbsp;--&nbsp;Destroy a mutex</DT
><DT
><A
HREF="sdlmutexp.html"
>SDL_mutexP</A
>&nbsp;--&nbsp;Lock a mutex</DT
><DT
><A
HREF="sdlmutexv.html"
>SDL_mutexV</A
>&nbsp;--&nbsp;Unlock a mutex</DT
><DT
><A
HREF="sdlcreatesemaphore.html"
>SDL_CreateSemaphore</A
>&nbsp;--&nbsp;Creates a new semaphore and assigns an initial value to it.</DT
><DT
><A
HREF="sdldestroysemaphore.html"
>SDL_DestroySemaphore</A
>&nbsp;--&nbsp;Destroys a semaphore that was created by <A
HREF="sdlcreatesemaphore.html"
>SDL_CreateSemaphore</A
>.</DT
><DT
><A
HREF="sdlsemwait.html"
>SDL_SemWait</A
>&nbsp;--&nbsp;Lock a semaphore and suspend the thread if the semaphore value is zero.</DT
><DT
><A
HREF="sdlsemtrywait.html"
>SDL_SemTryWait</A
>&nbsp;--&nbsp;Attempt to lock a semaphore but don't suspend the thread.</DT
><DT
><A
HREF="sdlsemwaittimeout.html"
>SDL_SemWaitTimeout</A
>&nbsp;--&nbsp;Lock a semaphore, but only wait up to a specified maximum time.</DT
><DT
><A
HREF="sdlsempost.html"
>SDL_SemPost</A
>&nbsp;--&nbsp;Unlock a semaphore.</DT
><DT
><A
HREF="sdlsemvalue.html"
>SDL_SemValue</A
>&nbsp;--&nbsp;Return the current value of a semaphore.</DT
><DT
><A
HREF="sdlcreatecond.html"
>SDL_CreateCond</A
>&nbsp;--&nbsp;Create a condition variable</DT
><DT
><A
HREF="sdldestroycond.html"
>SDL_DestroyCond</A
>&nbsp;--&nbsp;Destroy a condition variable</DT
><DT
><A
HREF="sdlcondsignal.html"
>SDL_CondSignal</A
>&nbsp;--&nbsp;Restart a thread wait on a condition variable</DT
><DT
><A
HREF="sdlcondbroadcast.html"
>SDL_CondBroadcast</A
>&nbsp;--&nbsp;Restart all threads waiting on a condition variable</DT
><DT
><A
HREF="sdlcondwait.html"
>SDL_CondWait</A
>&nbsp;--&nbsp;Wait on a condition variable</DT
><DT
><A
HREF="sdlcondwaittimeout.html"
>SDL_CondWaitTimeout</A
>&nbsp;--&nbsp;Wait on a condition variable, with timeout</DT
></DL
></DIV
><P
>SDL provides functions for creating threads, mutexes, semphores and condition variables.</P
><P
>In general, you must be very aware of concurrency and data integrity issues
when writing multi-threaded programs.  Some good guidelines include:
<P
></P
><UL
><LI
><P
>Don't call SDL video/event functions from separate threads</P
></LI
><LI
><P
>Don't use any library functions in separate threads</P
></LI
><LI
><P
>Don't perform any memory management in separate threads</P
></LI
><LI
><P
>Lock global variables which may be accessed by multiple threads</P
></LI
><LI
><P
>Never terminate threads, always set a flag and wait for them to quit</P
></LI
><LI
><P
>Think very carefully about all possible ways your code may interact</P
></LI
></UL
></P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>SDL's threading is not implemented on MacOS, due to that lack of preemptive thread support (Mac OS X dos nt suffer from this problem)</P
></BLOCKQUOTE
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