diff options
Diffstat (limited to 'missing')
-rw-r--r-- | missing/isnan.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/missing/isnan.c b/missing/isnan.c index 5846947f50..ed10bf5cd6 100644 --- a/missing/isnan.c +++ b/missing/isnan.c @@ -2,6 +2,20 @@ #include "ruby/missing.h" +/* + * isnan() may be a macro, a function or both. + * (The C99 standard defines that isnan() is a macro, though.) + * http://www.gnu.org/software/automake/manual/autoconf/Function-Portability.html + * + * macro only: uClibc + * both: GNU libc + * + * This file is compile if no isnan() function is available. + * (autoconf AC_REPLACE_FUNCS detects only the function.) + * The macro is detected by following #ifndef. + */ + +#ifndef isnan static int double_ne(double n1, double n2); int @@ -15,3 +29,4 @@ double_ne(double n1, double n2) { return n1 != n2; } +#endif |