Open System Services Library Calls Reference Manual (G06.28+, H06.05+)

OSS Library Calls (n - r) rint(3)
NAME
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rint - Rounds floating-point numbers to nearest integral value |
LIBRARY |
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRESRL |
G-series native OSS processes: /G/system/sysnn/zcresrl |
H-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL |
H-series OSS processes: /G/system/zdllnnn/zcredll |
SYNOPSIS
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#include <math.h> |
double rint( |
double x); |
PARAMETERS
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x ||
Is the double-precision floating-point value to be rounded. |
DESCRIPTION |
The rint() function returns the integral value (as a double) nearest the value of the x parameter |
in the direction of the current rounding mode. |
If the current rounding mode rounds in the direction of negative infinity, the rint() function is |
identical to the floor() function. If the current rounding mode rounds in the direction of positive |
infinity, the rint() function is identical to the ceil() function. |
NOTES |
The rint() function can be called only by native processes. |
This function supports both IEEE Std 754-1985 floating-point and Tandem floating-point values. |
IEEE values can include NaN and infinity, and the sign of 0.0 (zero) can be either positive or |
negative. Refer to the fp_class(3) reference page for a description of IEEE value classes. |
Guardian functions are available to convert between floating-point formats. Refer to the Guar- |
dian Programmer’s Guide for a discussion of floating-point conversions. |
Remember the following rules when using any special floating-point mode: |
|
• ||
Do not assume that functions such as printf( ) or tanh( ) behave correctly if you call |
them after setting a nondefault operating mode (such as rounding toward zero). Unless a |
function is documented as tolerating such modes, you should restore the default operat- |
ing mode before calling the function. |
|
• ||
The exception bits of the floating-point status register stay set until they are explicitly |
cleared. |
RETURN VALUES
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On successful completion, the rint() function returns the integral value (as a double) nearest the |
value of the x parameter in the direction of the current rounding mode. |
For IEEE floating-point values, when the value of x is positive or negative infinity, the rint() |
function returns the value of x. If the value of x is NaN, the function returns NaN. |
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