209 lines
4.8 KiB
HTML
209 lines
4.8 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of ECVT</TITLE>
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</HEAD><BODY>
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<H1>ECVT</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2016-03-15<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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ecvt, fcvt - convert a floating-point number to a string
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#include <<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>></B>
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<P>
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<B>char *ecvt(double </B><I>number</I><B>, int </B><I>ndigits</I><B>, int *</B><I>decpt</I><B>,</B>
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<B>int *</B><I>sign</I><B>);</B>
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<P>
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<B>char *fcvt(double </B><I>number</I><B>, int </B><I>ndigits</I><B>, int *</B><I>decpt</I><B>,</B>
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<B>int *</B><I>sign</I><B>);</B>
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<P>
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Feature Test Macro Requirements for glibc (see
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<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
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<P>
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<B>ecvt</B>(),
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<B>fcvt</B>():
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<DL COMPACT><DT id="1"><DD>
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<DL COMPACT>
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<DT id="2">Since glibc 2.12:<DD>
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<PRE>
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(_XOPEN_SOURCE >= 500) ! (_POSIX_C_SOURCE >= 200112L)
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|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
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|| /* Glibc versions <= 2.19: */ _SVID_SOURCE
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</PRE>
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<DT id="3">Before glibc 2.12:<DD>
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_SVID_SOURCE || _XOPEN_SOURCE >= 500
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</DL>
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</DL>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The
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<B>ecvt</B>()
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function converts <I>number</I> to a null-terminated
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string of <I>ndigits</I> digits (where <I>ndigits</I> is reduced to a
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system-specific limit determined by the precision of a
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<I>double</I>),
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and returns a pointer to the string.
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The high-order digit is nonzero, unless
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<I>number</I>
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is zero.
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The low order digit is rounded.
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The string itself does not contain a decimal point; however,
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the position of the decimal point relative to the start of the string
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is stored in <I>*decpt</I>.
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A negative value for <I>*decpt</I> means that
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the decimal point is to the left of the start of the string.
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If the sign of
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<I>number</I> is negative, <I>*sign</I> is set to a nonzero value,
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otherwise it is set to 0.
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If
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<I>number</I>
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is zero, it is unspecified whether <I>*decpt</I> is 0 or 1.
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<P>
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The
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<B>fcvt</B>()
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function is identical to
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<B>ecvt</B>(),
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except that
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<I>ndigits</I> specifies the number of digits after the decimal point.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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Both the
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<B>ecvt</B>()
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and
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<B>fcvt</B>()
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functions return a pointer to a
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static string containing the ASCII representation of <I>number</I>.
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The static string is overwritten by each call to
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<B>ecvt</B>()
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or
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<B>fcvt</B>().
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<A NAME="lbAF"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>ecvt</B>()
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</TD><TD>Thread safety</TD><TD>MT-Unsafe race:ecvt<BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>fcvt</B>()
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</TD><TD>Thread safety</TD><TD>MT-Unsafe race:fcvt<BR></TD></TR>
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</TABLE>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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SVr2;
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marked as LEGACY in POSIX.1-2001.
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POSIX.1-2008 removes the specifications of
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<B>ecvt</B>()
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and
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<B>fcvt</B>(),
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recommending the use of
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<B><A HREF="/cgi-bin/man/man2html?3+sprintf">sprintf</A></B>(3)
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instead (though
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<B><A HREF="/cgi-bin/man/man2html?3+snprintf">snprintf</A></B>(3)
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may be preferable).
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<A NAME="lbAH"> </A>
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<H2>NOTES</H2>
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Not all locales use a point as the radix character ("decimal point").
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<A NAME="lbAI"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?3+ecvt_r">ecvt_r</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+gcvt">gcvt</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+qecvt">qecvt</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+setlocale">setlocale</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+sprintf">sprintf</A></B>(3)
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<A NAME="lbAJ"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="4"><A HREF="#lbAB">NAME</A><DD>
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<DT id="5"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="6"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="7"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="8"><A HREF="#lbAF">ATTRIBUTES</A><DD>
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<DT id="9"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="10"><A HREF="#lbAH">NOTES</A><DD>
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<DT id="11"><A HREF="#lbAI">SEE ALSO</A><DD>
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<DT id="12"><A HREF="#lbAJ">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:39 GMT, March 31, 2021
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</BODY>
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</HTML>
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