# expm1f(3m) [sunos man page]

expm1(3M) Mathematical Library Functions expm1(3M)NAME

expm1, expm1f, expm1l - compute exponential functionSYNOPSIS

cc [ flag... ] file...[ library... ] #include <math.h> double expm1(double x); float expm1f(float x); long double expm1l(long double x);-lmDESCRIPTION

These functions compute e**x-1.0.RETURN VALUES

Upon successful completion, these functions return e**x-1.0. If x is NaN, a NaN is returned. If x is +-0, +-0 is returned. If x is,-Infis returned. If x is +Inf, x is returned.-1ERRORS

These functions will fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception is raised.USAGE

The value of expm1(x) can be more accurate than exp(x)-1.0 for small values of x. The expm1() and log1p(3M) functions are useful for financial calculations of ((1+x)**n-1)/x, namely: expm1(n * log1p(x))/x when x is very small (for example, when performing calculations with a small daily interest rate). These functions also simplify writing accurate inverse hyperbolic functions. An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.ATTRIBUTES

See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+SEE ALSO

exp(3M), feclearexcept(3M), fetestexcept(3M), ilogb(3M), log1p(3M), math.h(3HEAD), attributes(5), standards(5)SunOS 5.101 Nov 2003 expm1(3M)

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NAME

expm1, expm1f, expm1l - compute exponential functionSYNOPSIS

cc [ flag... ] file...[ library... ] #include <math.h> double expm1(double x); float expm1f(float x); long double expm1l(long double x);-lmDESCRIPTION

These functions compute e**x-1.0.RETURN VALUES

Upon successful completion, these functions return e**x-1.0. If x is NaN, a NaN is returned. If x is +-0, +-0 is returned. If x is,-Infis returned. If x is +Inf, x is returned.-1ERRORS

These functions will fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception is raised.USAGE

The value of expm1(x) can be more accurate than exp(x)-1.0 for small values of x. The expm1() and log1p(3M) functions are useful for financial calculations of ((1+x)**n-1)/x, namely: expm1(n * log1p(x))/x when x is very small (for example, when performing calculations with a small daily interest rate). These functions also simplify writing accurate inverse hyperbolic functions. An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.ATTRIBUTES

See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+SEE ALSO

exp(3M), feclearexcept(3M), fetestexcept(3M), ilogb(3M), log1p(3M), math.h(3HEAD), attributes(5), standards(5)SunOS 5.101 Nov 2003 expm1(3M)