Mercurial > sdl-ios-xcode
view test/testloadso.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 | 2c835d58faad |
children | 9de326b3099c |
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/* Test program to test dynamic loading with the loadso subsystem. */ #include <stdio.h> #include <stdlib.h> #include "SDL.h" typedef int (*fntype) (const char *); int main(int argc, char *argv[]) { int retval = 0; int hello = 0; const char *libname = NULL; const char *symname = NULL; void *lib = NULL; fntype fn = NULL; if (argc != 3) { const char *app = argv[0]; fprintf(stderr, "USAGE: %s <library> <functionname>\n", app); fprintf(stderr, " %s --hello <lib with puts()>\n", app); return 1; } /* Initialize SDL */ if (SDL_Init(0) < 0) { fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError()); return 2; } if (strcmp(argv[1], "--hello") == 0) { hello = 1; libname = argv[2]; symname = "puts"; } else { libname = argv[1]; symname = argv[2]; } lib = SDL_LoadObject(libname); if (lib == NULL) { fprintf(stderr, "SDL_LoadObject('%s') failed: %s\n", libname, SDL_GetError()); retval = 3; } else { fn = (fntype) SDL_LoadFunction(lib, symname); if (fn == NULL) { fprintf(stderr, "SDL_LoadFunction('%s') failed: %s\n", symname, SDL_GetError()); retval = 4; } else { printf("Found %s in %s at %p\n", symname, libname, fn); if (hello) { printf("Calling function...\n"); fflush(stdout); fn(" HELLO, WORLD!\n"); printf("...apparently, we survived. :)\n"); printf("Unloading library...\n"); fflush(stdout); } } SDL_UnloadObject(lib); } SDL_Quit(); return (0); }