Guardian Native C Library Calls Reference Manual (G06.28+, H06.05+)

ceil(3) Guardian Native C Library Calls Reference Manual
NAME
ceil - Rounds floating-point numbers to floating-point integers
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
#include <math.h>
double ceil(
double x);
PARAMETERS
x Specifies the double value to be rounded.
DESCRIPTION
The ceil() function returns the smallest floating-point integral value not less than the x parameter.
NOTES
This function supports both IEEE Std 754-1985 floating-point and Tandem floating-point values
in the native environment. 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.
RETURN VALUES
Upon successful completion, the ceil() function returns the smallest integral value not less than
x. For IEEE floating-point values, if the value of x is NaN, NaN is returned. If x is positive or
negative infinity or positive or negative zero, the value of x is returned.
ERRORS
No error values are returned. This function does not set errno.
RELATED INFORMATION
Functions: abs(3), fabs(3), floor(3), fmod(3), fp_class(3), isnan(3).
STANDARDS CONFORMANCE
This function conforms to the XPG4 Version 2 specification with extensions when used for IEEE
floating-point data. This function conforms to the XPG4 Version 2 specification without exten-
sions when used for Tandem floating-point data.
The XPG4 Version 2 specification leaves some features to the implementing vendor to define.
The following features are affected in the HP implementation:
• For IEEE floating-point data, errno is not set to [EDOM] when the value of x is NaN.
• The ceil() function cannot cause overflow, so errno is not set to [ERANGE].
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