1 '\" te 2 .\" Copyright 1989 AT&T. Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved. Portions Copyright (c) 1992, X/Open Company Limited, All Rights Reserved. 3 .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at 4 .\" http://www.opengroup.org/bookstore/. 5 .\" The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. 6 .\" This notice shall appear on any product containing this material. 7 .\" 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. 8 .\" 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. 9 .\" 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] 10 .TH ECVT 3C "May 18, 2004" 11 .SH NAME 12 ecvt, fcvt, gcvt \- convert floating-point number to string 13 .SH SYNOPSIS 14 .LP 15 .nf 16 #include <stdlib.h> 17 18 \fBchar *\fR\fBecvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBint *restrict\fR \fIdecpt\fR, \fBint *restrict\fR \fIsign\fR); 19 .fi 20 21 .LP 22 .nf 23 \fBchar *\fR\fBfcvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBint *restrict\fR \fIdecpt\fR, \fBint *restrict\fR \fIsign\fR); 24 .fi 25 26 .LP 27 .nf 28 \fBchar *\fR\fBgcvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBchar *\fR\fIbuf\fR); 29 .fi 30 31 .SH DESCRIPTION 32 .sp 33 .LP 34 The \fBecvt()\fR, \fBfcvt()\fR and \fBgcvt()\fR functions convert 35 floating-point numbers to null-terminated strings. 36 .SS "\fBecvt()\fR" 37 .sp 38 .LP 39 The \fBecvt()\fR function converts \fIvalue\fR to a null-terminated string of 40 \fIndigit\fR digits (where \fIndigit\fR is reduced to an unspecified limit 41 determined by the precision of a \fBdouble\fR) and returns a pointer to the 42 string. The high-order digit is non-zero, unless the value is 0. The 43 low-order digit is rounded. The position of the radix character relative to 44 the beginning of the string is stored in the integer pointed to by \fIdecpt\fR 45 (negative means to the left of the returned digits). The radix character is not 46 included in the returned string. If the sign of the result is negative, the 47 integer pointed to by \fIsign\fR is non-zero, otherwise it is 0. 48 .sp 49 .LP 50 If the converted value is out of range or is not representable, the contents of 51 the returned string are unspecified. 52 .SS "\fBfcvt()\fR" 53 .sp 54 .LP 55 The \fBfcvt()\fR function is identical to \fBecvt()\fR except that \fIndigit\fR 56 specifies the number of digits desired after the radix point. The total number 57 of digits in the result string is restricted to an unspecified limit as 58 determined by the precision of a \fBdouble\fR. 59 .SS "\fBgcvt()\fR" 60 .sp 61 .LP 62 The \fBgcvt()\fR function converts \fIvalue\fR to a null-terminated string 63 (similar to that of the \fB%g\fR format of \fBprintf\fR(3C)) in the array 64 pointed to by \fIbuf\fR and returns \fIbuf\fR. It produces \fIndigit\fR 65 significant digits (limited to an unspecified value determined by the precision 66 of a \fBdouble\fR) in \fB%f\fR if possible, or \fB%e\fR (scientific notation) 67 otherwise. A minus sign is included in the returned string if \fIvalue\fR is 68 less than 0. A radix character is included in the returned string if 69 \fIvalue\fR is not a whole number. Trailing zeros are suppressed where 70 \fIvalue\fR is not a whole number. The radix character is determined by the 71 current locale. If \fBsetlocale\fR(3C) has not been called successfully, the 72 default locale, POSIX, is used. The default locale specifies a period 73 (\fB\&.\fR) as the radix character. The \fBLC_NUMERIC\fR category determines 74 the value of the radix character within the current locale. 75 .SH RETURN VALUES 76 .sp 77 .LP 78 The \fBecvt()\fR and \fBfcvt()\fR functions return a pointer to a 79 null-terminated string of digits. 80 .sp 81 .LP 82 The \fBgcvt()\fR function returns \fIbuf\fR. 83 .SH ERRORS 84 .sp 85 .LP 86 No errors are defined. 87 .SH USAGE 88 .sp 89 .LP 90 The return values from \fBecvt()\fR and \fBfcvt()\fR might point to 91 thread-specific data that can be overwritten by subsequent calls to these 92 functions by the same thread. 93 .sp 94 .LP 95 For portability to implementations conforming to earlier versions of Solaris, 96 \fBsprintf\fR(3C) is preferred over this function. 97 .SH ATTRIBUTES 98 .sp 99 .LP 100 See \fBattributes\fR(5) for descriptions of the following attributes: 101 .sp 102 103 .sp 104 .TS 105 box; 106 c | c 107 l | l . 108 ATTRIBUTE TYPE ATTRIBUTE VALUE 109 _ 110 Interface Stability Standard 111 _ 112 MT-Level Safe 113 .TE 114 115 .SH SEE ALSO 116 .sp 117 .LP 118 \fBprintf\fR(3C), \fBsetlocale\fR(3C), \fBsprintf\fR(3C), \fBattributes\fR(5), 119 \fBstandards\fR(5)