Mercurial > sdl-ios-xcode
view docs/man3/SDL_SemWait.3 @ 461:1d36f593078a
Date: Thu, 18 Jul 2002 23:51:40 +0200 (MEST)
From: Krister Walfridsson
Subject: [SDL] src/joystick/bsd/SDL_sysjoystick.c patch
The *BSD USB HID joystick code has two serious bugs:
1. If a joystick reports unhandled hid_input usage (for example HUG_RZ or
HUG_DIAL), then the last handled value will be overwritten with an
arbitrary value. (Fixed in the patch below by adding a default case.)
2. The current code does only handle logical coordinates in the range 0-255,
while a big part of available joysticks report -128 - 127. (This is solved
in the patch below by first center the range around 0, and then stretch
it to the correct range.)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 20 Aug 2002 06:08:42 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_SemWait" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_SemWait\- Lock a semaphore and suspend the thread if the semaphore value is zero\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" #include "SDL_thread\&.h" .sp \fBint \fBSDL_SemWait\fP\fR(\fBSDL_sem *sem\fR); .SH "DESCRIPTION" .PP \fBSDL_SemWait()\fP suspends the calling thread until either the semaphore pointed to by \fBsem\fR has a positive value, the call is interrupted by a signal or error\&. If the call is successful it will atomically decrement the semaphore value\&. .PP After \fBSDL_SemWait()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR if successful or \fB-1\fR if there was an error (leaving the semaphore unchanged)\&. .SH "EXAMPLES" .PP .PP .nf \f(CWif (SDL_SemWait(my_sem) == -1) { return WAIT_FAILED; } \&.\&.\&. SDL_SemPost(my_sem);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00