Mercurial > sdl-ios-xcode
view test/testmmousetablet.c @ 2752:edd2839b36f7
http://sources.redhat.com/ml/newlib/2002/msg00230.html
Stephen L Moshier wrote:
>
> pow(x,y) returns 0 when x is very close to -1.0 and y is very large.
> The following test program prints
>
> pow(1.0000000000000002e+00 4.5035996273704970e+15) = 2.7182818284590455e+00
> pow(-1.0000000000000002e+00 4.5035996273704970e+15) =0.0000000000000000e+00
> pow(9.9999999999999978e-01 4.5035996273704970e+15) = 3.6787944117144222e-01
> pow(-9.9999999999999978e-01 4.5035996273704970e+15) = 0.0000000000000000e+00
>
> which is incorrect for the negative arguments raised to an odd integer
> power.
>
> -----
> double pow (double, double);
>
> int
> main ()
> {
> double x, y, z;
>
> x = 1.0 + pow (2.0, -52.0);
> y = 1.0 + pow (2.0, 52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = 1.0 - pow (2.0, -52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> }
> -----
>
> Here is a patch for newlib/libm/math/epow.c:
Patch checked in and duplicated for ef_pow.c. Thanks.
-- Jeff J.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 15 Sep 2008 04:31:30 +0000 |
parents | ae653575d4af |
children | 975fd903466b |
line wrap: on
line source
#include <stdio.h> #include "SDL.h" SDL_Surface *screen; int quit = 0; int main() { SDL_Event event; int mice; int i; printf("Initing...\n"); if (SDL_Init(0) != 0) { return 1; } if (SDL_InitSubSystem(SDL_INIT_VIDEO) != 0) { return 1; } else { screen = SDL_SetVideoMode(640, 480, 32, SDL_DOUBLEBUF); } mice = SDL_GetNumMice(); printf("%d pointing devices found\n", mice); for (i = 0; i < mice; ++i) { printf("device index: %d name:%s\n", i, SDL_GetMouseName(i)); } while (quit != 1) { if (SDL_PollEvent(&event) == 0) { } else { switch (event.type) { case SDL_MOUSEMOTION: printf ("Device id: %d x: %d y: %d relx: %d rely: %d pressure: %d\n \ pressure_max: %d pressure_min: %d current cursor:%d\n", event.motion.which, event.motion.x, event.motion.y, event.motion.xrel, event.motion.yrel, event.motion.pressure, event.motion.pressure_max, event.motion.pressure_min, event.motion.cursor); break; case SDL_PROXIMITYIN: printf("proximity in id: %d x: %d y: %d\n", (int) event.proximity.which, event.proximity.x, event.proximity.y); break; case SDL_PROXIMITYOUT: printf("proximity out id: %d x: %d y: %d\n", (int) event.proximity.which, event.proximity.x, event.proximity.y); break; case SDL_MOUSEBUTTONDOWN: printf("mouse button down id: %d button:%d\n", event.button.which, event.button.button); break; case SDL_MOUSEBUTTONUP: printf("mouse button up id: %d button: %d\n", event.button.which, event.button.button); break; case SDL_QUIT: printf("Quitting\n"); SDL_QuitSubSystem(SDL_INIT_VIDEO); SDL_Quit(); quit = 1; break; } } } return 0; }