Standards
| Standards / Extensions | C or C++ | Dependencies |
|---|---|---|
| C/C++ DFP | both | z/OS® V1.11 |
Format
#define __STDC_WANT_DEC_FP__
#include <math.h>
_Decimal32 expm1d32(_Decimal32 x);
_Decimal64 expm1d64(_Decimal64 x);
_Decimal128 expm1d128(_Decimal128 x);
_Decimal32 expm1(_Decimal32 x); /* C++ only */
_Decimal64 expm1(_Decimal64 x); /* C++ only */
_Decimal128 expm1(_Decimal128 x); /* C++ only */General description
The expm1() functions
calculate the function: 
Notes:
- These functions work in IEEE decimal floating-point format. See IEEE decimal floating-pointIEEE Decimal Floating-Point for more information.
- To use IEEE decimal floating-point, the hardware must have the Decimal Floating-Point Facility installed.
Returned value
If successful, expm1() returns the above function calculated on x.
If unsuccessful, expm1() may fail as follows:
- If x is negative and exceeds an internally defined large value, expm1() functions will return -1.0.
- If the value of the function overflows, expm1() functions will return HUGE_VAL_D32 or HUGE_VAL_D64 or HUGE_VAL_D128 as appropriate, and set errno to ERANGE.
Example
⁄* CELEBE13
This example illustrates the expm1d32() function.
*⁄
#define __STDC_WANT_DEC_FP__
#include <math.h>
#include <stdio.h>
void main(void)
{
_Decimal32 x, y;
x = 2.5DF;
y = expm1d32(x);
printf("expm1d32(%Hf) = %Hf\n", x, y);
}