int ilogb(float x);
float ldexp(float x, int e);
//float log(float x);
+float logn(float x, float base);
float log10(float x);
float log1p(float x);
float log2(float x);
const float M_LOG10E = 0.43429448190325182765; /* log_10 e */
const float M_LN2 = 0.69314718055994530942; /* log_e 2 */
const float M_LN10 = 2.30258509299404568402; /* log_e 10 */
-const float M_PI = 3.14159265358979323846; /* pi */
+// -Wdouble-declaration
+#define M_PI 3.14159265358979323846 /* pi */
const float M_PI_2 = 1.57079632679489661923; /* pi/2 */
const float M_PI_4 = 0.78539816339744830962; /* pi/4 */
const float M_1_PI = 0.31830988618379067154; /* 1/pi */