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Copyright (c) 1999, Sun Microsystems, Inc. All Rights Reserved
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. 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]
ECONVERT 3C "May 3, 1999"
NAME
econvert, fconvert, gconvert, seconvert, sfconvert, sgconvert, qeconvert, qfconvert, qgconvert - output conversion
SYNOPSIS

#include <floatingpoint.h>

char *econvert(double value, int ndigit, int *decpt, int *sign,
 char *buf);

char *fconvert(double value, int ndigit, int *decpt, int *sign,
 char *buf);

char *gconvert(double value, int ndigit, int trailing, char *buf);

char *seconvert(single *value, int ndigit, int *decpt, int *sign,
 char *buf);

char *sfconvert(single *value, int ndigit, int *decpt, int *sign,
 char *buf);

char *sgconvert(single *value, int ndigit, int trailing, char *buf);

char *qeconvert(quadruple *value, int ndigit, int *decpt, int *sign,
 char *buf);

char *qfconvert(quadruple *value, int ndigit, int *decpt, int *sign
 char *buf);

char *qgconvert(quadruple *value, int ndigit, int trailing, char *buf);
DESCRIPTION

The econvert() function converts the value to a null-terminated string of ndigit ASCII digits in buf and returns a pointer to buf. buf should contain at least ndigit+1 characters. The position of the decimal point relative to the beginning of the string is stored indirectly through decpt. Thus buf == "314" and *decpt == 1 corresponds to the numerical value 3.14, while buf == "314" and *decpt == -1 corresponds to the numerical value .0314. If the sign of the result is negative, the word pointed to by sign is nonzero; otherwise it is zero. The least significant digit is rounded.

The fconvert() function works much like econvert(), except that the correct digit has been rounded as if for sprintf(%w.nf) output with n=ndigit digits to the right of the decimal point. ndigit can be negative to indicate rounding to the left of the decimal point. The return value is a pointer to buf. buf should contain at least 310+max(0,ndigit) characters to accomodate any double-precision value.

The gconvert() function converts the value to a null-terminated ASCII string in buf and returns a pointer to buf. It produces ndigit significant digits in fixed-decimal format, like sprintf(%w.nf), if possible, and otherwise in floating-decimal format, like sprintf(%w.ne); in either case buf is ready for printing, with sign and exponent. The result corresponds to that obtained by

(void) sprintf(buf,``%w.ng'',value) ;

If trailing = 0, trailing zeros and a trailing point are suppressed, as in sprintf(%g). If trailing != 0, trailing zeros and a trailing point are retained, as in sprintf(%#g).

The seconvert(), sfconvert(), and sgconvert() functions are single-precision versions of these functions, and are more efficient than the corresponding double-precision versions. A pointer rather than the value itself is passed to avoid C's usual conversion of single-precision arguments to double.

The qeconvert(), qfconvert(), and qgconvert() functions are quadruple-precision versions of these functions. The qfconvert() function can overflow the decimal_record field ds if value is too large. In that case, buf[0] is set to zero.

The ecvt(), fcvt() and gcvt() functions are versions of econvert(), fconvert(), and gconvert(), respectively, that are documented on the ecvt(3C) manual page. They constitute the default implementation of these functions and conform to the X/Open CAE Specification, System Interfaces and Headers, Issue 4, Version 2.

USAGE

IEEE Infinities and NaNs are treated similarly by these functions. ``NaN'' is returned for NaN, and ``Inf'' or ``Infinity'' for Infinity. The longer form is produced when ndigit >= 8.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE
MT-Level MT-Safe
SEE ALSO

ecvt(3C),sprintf(3C), attributes(5)