Mercurial > sdl-ios-xcode
view docs/man3/SDL_JoystickGetBall.3 @ 3068:b21348d47cab
Fixed bug #633
Description From Michael Stone 2008-09-25 19:27:29 (-) [reply]
To determine whether a pid is occupied with the kill(pid, 0) idiom, you have to
test
#include <signal.h>
#include <errno.h>
kill(pid, 0) < 0 && errno == ESRCH
not just
#include <signal.h>
kill(pid, 0) < 0
otherwise you get incorrect results when pid is running as a different user
(causing kill(pid, 0) to return -1 + EPERM).
src/audio/alsa/SDL_alsa_audio.c is certainly affected by this bug in both
1.2.13 and 1.3-trunk. It probably occurs in other places as well.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 17 Feb 2009 05:17:51 +0000 |
| parents | 546f7c1eb755 |
| children | 1238da4a7112 |
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.TH "SDL_JoystickGetBall" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_JoystickGetBall \- Get relative trackball motion .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_JoystickGetBall\fP\fR(\fBSDL_Joystick *joystick, int ball, int *dx, int *dy\fR); .SH "DESCRIPTION" .PP Get the \fBball\fR axis change\&. .PP Trackballs can only return relative motion since the last call to \fBSDL_JoystickGetBall\fP, these motion deltas a placed into \fBdx\fR and \fBdy\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR on success or \fB-1\fR on failure .SH "EXAMPLES" .PP .PP .nf \f(CWint delta_x, delta_y; SDL_Joystick *joy; \&. \&. \&. SDL_JoystickUpdate(); if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1) printf("TrackBall Read Error! "); printf("Trackball Delta- X:%d, Y:%d ", delta_x, delta_y);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_JoystickNumBalls\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00