Computes exponential functions.
#include <math.h> float expm1f (x) float x; long double expm1l (x) long double x; double expm1 (x) double x;
The expm1f, expm1l, and expm1 subroutines compute ex- 1.0.
An application wishing to check for error situations should set the errno global variable to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. Upon return, if errno is nonzero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is nonzero, an error has occurred.
| x | Specifies the value to be computed. |
Upon successful completion, the expm1f, expm1l, and expm1 subroutines return ex- 1.0.
If the correct value would cause overflow, a range error occurs and the expm1f, expm1l, and expm1 subroutines return the value of the macro HUGE_VALF, HUGE_VALL, and HUGE_VAL, respectively.
If x is NaN, a NaN is returned.
If x is ±0, ±0 is returned.
If x is -Inf, -1 is returned.
If x is +Inf, x is returned.
If x is subnormal, a range error may occur and x is returned.
exp, expf, or expl Subroutine, feclearexcept Subroutine, fetestexcept Subroutine, ilogbf, ilogbl, or ilogb Subroutine, and log, logf, or logl Subroutine.
math.h in AIX 5L Version 5.2 Files Reference.