math: Improve comments, disable errno handling by default
Improve comments in math_config.h.
Set WANT_ERRNO to 0 by default.
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
diff --git a/math/math_config.h b/math/math_config.h
index 7a1cc81..85fc584 100644
--- a/math/math_config.h
+++ b/math/math_config.h
@@ -12,12 +12,17 @@
#include <stdint.h>
#ifndef WANT_ROUNDING
-/* Correct special case results in non-nearest rounding modes. */
+/* If defined to 1, return correct results for special cases in non-nearest
+ rounding modes (logf (1.0f) returns 0.0f with FE_DOWNWARD rather than -0.0f).
+ This may be set to 0 if there is no fenv support or if math functions only
+ get called in round to nearest mode. */
# define WANT_ROUNDING 1
#endif
#ifndef WANT_ERRNO
-/* Set errno according to ISO C with (math_errhandling & MATH_ERRNO) != 0. */
-# define WANT_ERRNO 1
+/* If defined to 1, set errno in math functions according to ISO C. Many math
+ libraries do not set errno, so this is 0 by default. It may need to be
+ set to 1 if math.h has (math_errhandling & MATH_ERRNO) != 0. */
+# define WANT_ERRNO 0
#endif
#ifndef WANT_ERRNO_UFLOW
/* Set errno to ERANGE if result underflows to 0 (in all rounding modes). */