Manual Section... (3) - page: expl NAMEexp, expf, expl - base-e
exponential function #include <math.h> double exp(double x);
float expf(float x); long double expl(long double x); Link with
-lm. Feature Test Macro Requirements for glibc (see
feature_test_macros(7)): DESCRIPTIONThe exp() function returns
the value of e (the base of natural logarithms) raised to the
power of x. RETURN VALUEOn success, these functions return the
exponential value of x. If x is a NaN, a NaN is returned. If x
is positive infinity, positive infinity is returned. If x is
negative infinity, +0 is returned. If the result underflows, a
range error occurs, and zero is returned. ERRORSSee
math_error(7) for information on how to determine whether an
error has occurred when calling these functions. The following
errors can occur: - Range error, overflow - errno is set to
ERANGE. An overflow floating-point exception (FE_OVERFLOW) is
raised. - Range error, underflow - errno is set to ERANGE. An
underflow floating-point exception (FE_UNDERFLOW