Ruby: missing/isnan.c Source File

00001 /* public domain rewrite of isnan(3) */
00002 
00003 #include "ruby/missing.h"
00004 
00005 /*
00006  * isnan() may be a macro, a function or both.
00007  * (The C99 standard defines that isnan() is a macro, though.)
00008  * http://www.gnu.org/software/automake/manual/autoconf/Function-Portability.html
00009  *
00010  * macro only: uClibc
00011  * both: GNU libc
00012  *
00013  * This file is compile if no isnan() function is available.
00014  * (autoconf AC_REPLACE_FUNCS detects only the function.)
00015  * The macro is detected by following #ifndef.
00016  */
00017 
00018 #ifndef isnan
00019 static int double_ne(double n1, double n2);
00020 
00021 int
00022 isnan(double n)
00023 {
00024     return double_ne(n, n);
00025 }
00026 
00027 static int
00028 double_ne(double n1, double n2)
00029 {
00030     return n1 != n2;
00031 }
00032 #endif
00033