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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH float.h 3HEAD "17 Dec 2003" "SunOS 5.11" "Headers" .SH NAME float.h, float \- floating types .SH SYNOPSIS .LP .nf #include <\fBfloat.h\fR> .fi .SH DESCRIPTION .sp .LP The characteristics of floating types are defined in terms of a model that describes a representation of floating-point numbers and values that provide information about an implementation's floating-point arithmetic. .sp .LP The following parameters are used to define the model for each floating-point type: .sp .ne 2 .mk .na \fB\fIs\fR\fR .ad .RS 6n .rt sign (\(+-1) .RE .sp .ne 2 .mk .na \fB\fIb\fR\fR .ad .RS 6n .rt base or radix of exponent representation (an integer >1) .RE .sp .ne 2 .mk .na \fB\fIe\fR\fR .ad .RS 6n .rt exponent (an integer between a minimum e(min) and a maximum e(max)) .RE .sp .ne 2 .mk .na \fB\fIp\fR\fR .ad .RS 6n .rt precision (the number of base-\fIb\fR digits in the significand) .RE .sp .ne 2 .mk .na \fB\fIf\fR(\fIk\fR)\fR .ad .RS 6n .rt non-negative integers less than \fIb\fR (the significand digits) .RE .sp .LP In addition to normalized floating-point numbers (\fIf\fR(1)>0 if \fIx\fR\(!=0), floating types might be able to contain other kinds of floating-point numbers, such as subnormal floating-point numbers (x\(!=0, e=e(min), f(1)=0) and unnormalized floating-point numbers (x\(!=0, e=e(min), f(1)=0), and values that are not floating-point numbers, such as infinities and NaNs. A \fBNaN\fR is an encoding signifying Not-a-Number. A \fBquiet NaN\fR propagates through almost every arithmetic operation without raising a floating-point exception; a \fBsignaling NaN\fR generally raises a floating-point exception when occurring as an arithmetic operand. .sp .LP The accuracy of the library functions in \fBmath.h\fR(3HEAD) and \fBcomplex.h\fR(3HEAD) that return floating-point results is defined on the \fBlibm\fR(3LIB) manual page. .sp .LP All integer values in the <\fBfloat.h\fR> header, except \fBFLT_ROUNDS\fR, are constant expressions suitable for use in \fB#if\fR preprocessing directives; all floating values are constant expressions. All except \fBDECIMAL_DIG\fR, \fBFLT_EVAL_METHOD\fR, \fBFLT_RADIX\fR, and \fBFLT_ROUNDS\fR have separate names for all three floating-point types. The floating-point model representation is provided for all values except \fBFLT_EVAL_METHOD\fR and \fBFLT_ROUNDS\fR. .sp .LP The rounding mode for floating-point addition is characterized by the value of \fBFLT_ROUNDS\fR: .sp .ne 2 .mk .na \fB\fB-1\fR\fR .ad .RS 6n .rt Indeterminable. .RE .sp .ne 2 .mk .na \fB\fB0\fR\fR .ad .RS 6n .rt Toward zero. .RE .sp .ne 2 .mk .na \fB\fB1\fR\fR .ad .RS 6n .rt To nearest. .RE .sp .ne 2 .mk .na \fB\fB2\fR\fR .ad .RS 6n .rt Toward positive infinity. .RE .sp .ne 2 .mk .na \fB\fB3\fR\fR .ad .RS 6n .rt Toward negative infinity. .RE .sp .LP The values of operations with floating operands and values subject to the usual arithmetic conversions and of floating constants are evaluated to a format whose range and precision might be greater than required by the type. The use of evaluation formats is characterized by the architecture-dependent value of \fBFLT_EVAL_METHOD\fR: .sp .ne 2 .mk .na \fB\fB-1\fR\fR .ad .RS 6n .rt Indeterminable. .RE .sp .ne 2 .mk .na \fB\fB0\fR\fR .ad .RS 6n .rt Evaluate all operations and constants just to the range and precision of the type. .RE .sp .ne 2 .mk .na \fB\fB1\fR\fR .ad .RS 6n .rt Evaluate operations and constants of type float and double to the range and precision of the double type; evaluate long double operations and constants to the range and precision of the long double type. .RE .sp .ne 2 .mk .na \fB\fB2\fR\fR .ad .RS 6n .rt Evaluate all operations and constants to the range and precision of the long double type. .RE .sp .LP The values given in the following list are defined as constants. .RS +4 .TP .ie t \(bu .el o Radix of exponent representation, \fIb\fR. .sp .in +2 .nf FLT_RADIX .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Number of base-\fBFLT_RADIX\fR digits in the floating-point significand, \fIp\fR. .sp .in +2 .nf FLT_MANT_DIG DBL_MANT_DIG LDBL_MANT_DIG .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Number of decimal digits, \fIn\fR, such that any floating-point number in the widest supported floating type with \fIp\fR(max) radix \fIb\fR digits can be rounded to a floating-point number with \fIn\fR decimal digits and back again without change to the value. .sp .in +2 .nf DECIMAL_DIG .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Number of decimal digits, \fIq\fR, such that any floating-point number with \fIq\fR decimal digits can be rounded into a floating-point number with \fIp\fR radix \fIb\fR digits and back again without change to the \fIq\fR decimal digits. .sp .in +2 .nf FLT_DIG DBL_DIG LDBL_DIG .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Minimum negative integer such that \fBFLT_RADIX\fR raised to that power minus 1 is a normalized floating-point number, e(min). .sp .in +2 .nf FLT_MIN_EXP DBL_MIN_EXP LDBL_MIN_EXP .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Minimum negative integer such that 10 raised to that power is in the range of normalized floating-point numbers. .sp .in +2 .nf FLT_MIN_10_EXP DBL_MIN_10_EXP LDBL_MIN_10_EXP .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Maximum integer such that \fBFLT_RADIX\fR raised to that power minus 1 is a representable finite floating-point number, e(max). .sp .in +2 .nf FLT_MAX_EXP DBL_MAX_EXP LDBL_MAX_EXP .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Maximum integer such that 10 raised to that power is in the range of representable finite floating-point numbers. .sp .in +2 .nf FLT_MAX_10_EXP DBL_MAX_10_EXP LDBL_MAX_10_EXP .fi .in -2 .RE .sp .LP The values given in the following list are defined as constant expressions with values that are greater than or equal to those shown: .RS +4 .TP .ie t \(bu .el o Maximum representable finite floating-point number. .sp .in +2 .nf FLT_MAX DBL_MAX LDBL_MAX .fi .in -2 .RE .sp .LP The values given in the following list are defined as constant expressions with implementation-defined (positive) values that are less than or equal to those shown: .RS +4 .TP .ie t \(bu .el o The difference between 1 and the least value greater than 1 that is representable in the given floating-point type, \fIb\fR^1 -\fI p\fR. .sp .in +2 .nf FLT_EPSILON DBL_EPSILON LDBL_EPSILON .fi .in -2 .RE .RS +4 .TP .ie t \(bu .el o Minimum normalized positive floating-point number, \fIb\fR^e(min)^-1. .sp .in +2 .nf FLT_MIN DBL_MIN LDBL_MIN .fi .in -2 .RE .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ Interface StabilityStandard .TE .SH SEE ALSO .sp .LP \fBcomplex.h\fR(3HEAD), \fBmath.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)