diff options
| -rw-r--r-- | include/c99_math.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/c99_math.h b/include/c99_math.h index 5d4f5359db4..0a359ebb762 100644 --- a/include/c99_math.h +++ b/include/c99_math.h @@ -40,6 +40,11 @@ #if defined(_MSC_VER) +/* This is to ensure that we get M_PI, etc. definitions */ +#if !defined(_USE_MATH_DEFINES) +#error _USE_MATH_DEFINES define required when building with MSVC +#endif + #if _MSC_VER < 1800 #define isfinite(x) _finite((double)(x)) #define isnan(x) _isnan((double)(x)) |