Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame^] | 1 | /* Portable fmod(x, y) implementation for systems that don't have it */ |
2 | |||||
3 | #include <math.h> | ||||
4 | #include <errno.h> | ||||
5 | |||||
6 | extern int errno; | ||||
7 | |||||
8 | double | ||||
9 | fmod(x, y) | ||||
10 | double x, y; | ||||
11 | { | ||||
12 | double i, f; | ||||
13 | |||||
14 | if (y == 0.0) { | ||||
15 | errno = EDOM; | ||||
16 | return 0.0; | ||||
17 | } | ||||
18 | |||||
19 | /* return f such that x = i*y + f for some integer i | ||||
20 | such that |f| < |y| and f has the same sign as x */ | ||||
21 | |||||
22 | i = floor(x/y); | ||||
23 | f = x - i*y; | ||||
24 | if ((x < 0.0) != (y < 0.0)) | ||||
25 | f = f-y; | ||||
26 | return f; | ||||
27 | } |