.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
+.\" %%%LICENSE_START(VERBATIM)
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
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+.\"
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+.\" %%%LICENSE_END
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.\" References consulted:
.\" Linux libc source code
.\" Modified Sat Jul 24 19:40:39 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Fri Jun 25 12:10:47 1999 by Andries Brouwer (aeb@cwi.nl)
.\"
-.TH ECVT 3 1999-06-25 "" "Linux Programmer's Manual"
+.TH ECVT 3 2016-03-15 "" "Linux Programmer's Manual"
.SH NAME
ecvt, fcvt \- convert a floating-point number to a string
.SH SYNOPSIS
.B #include <stdlib.h>
-.sp
+.PP
.BI "char *ecvt(double " number ", int " ndigits ", int *" decpt ,
.BI "int *" sign );
-.sp
+.PP
.BI "char *fcvt(double " number ", int " ndigits ", int *" decpt ,
.BI "int *" sign );
+.PP
+.in -4n
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.in
+.PP
+.BR ecvt (),
+.BR fcvt ():
+.ad l
+.RS 4
+.PD 0
+.TP 4
+Since glibc 2.12:
+.nf
+(_XOPEN_SOURCE\ >=\ 500) ! (_POSIX_C_SOURCE\ >=\ 200112L)
+ || /* Glibc since 2.19: */ _DEFAULT_SOURCE
+ || /* Glibc versions <= 2.19: */ _SVID_SOURCE
+.fi
+.TP 4
+Before glibc 2.12:
+_SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500
+.\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
+.PD
+.RE
+.ad b
.SH DESCRIPTION
-The \fBecvt\fP() function converts \fInumber\fP to a null-terminated
-string of \fIndigits\fP digits (where \fIndigits\fP is reduced to an
-system-specific limit determined by the precision of a double),
-and returns a pointer to the string. The high-order digit is non-zero,
-unless
+The
+.BR ecvt ()
+function converts \fInumber\fP to a null-terminated
+string of \fIndigits\fP digits (where \fIndigits\fP is reduced to a
+system-specific limit determined by the precision of a
+.IR double ),
+and returns a pointer to the string.
+The high-order digit is nonzero, unless
.I number
-is zero. The low order digit is rounded.
+is zero.
+The low order digit is rounded.
The string itself does not contain a decimal point; however,
the position of the decimal point relative to the start of the string
-is stored in *\fIdecpt\fP. A negative value for *\fIdecpt\fP means that
-the decimal point is to the left of the start of the string. If the sign of
-\fInumber\fP is negative, *\fIsign\fP is set to a non-zero value, otherwise
-it's set to 0. If
+is stored in \fI*decpt\fP.
+A negative value for \fI*decpt\fP means that
+the decimal point is to the left of the start of the string.
+If the sign of
+\fInumber\fP is negative, \fI*sign\fP is set to a nonzero value,
+otherwise it is set to 0.
+If
.I number
-is zero, it is unspecified whether *\fIdecpt\fP is 0 or 1.
+is zero, it is unspecified whether \fI*decpt\fP is 0 or 1.
.PP
-The \fBfcvt\fP() function is identical to \fBecvt\fP(), except that
+The
+.BR fcvt ()
+function is identical to
+.BR ecvt (),
+except that
\fIndigits\fP specifies the number of digits after the decimal point.
-.SH "RETURN VALUE"
-Both the \fBecvt\fP() and \fBfcvt\fP() functions return a pointer to a
+.SH RETURN VALUE
+Both the
+.BR ecvt ()
+and
+.BR fcvt ()
+functions return a pointer to a
static string containing the ASCII representation of \fInumber\fP.
-The static string is overwritten by each call to \fBecvt\fP() or
-\fBfcvt\fP().
-.SH NOTES
-These functions are obsolete. Instead,
-.BR sprintf ()
-is recommended.
-Linux libc4 and libc5 specified the type of
-.I ndigits
-as
-.BR size_t .
-Not all locales use a point as the radix character (`decimal point').
-.SH "CONFORMING TO"
+The static string is overwritten by each call to
+.BR ecvt ()
+or
+.BR fcvt ().
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lb lb lb
+l l l.
+Interface Attribute Value
+T{
+.BR ecvt ()
+T} Thread safety MT-Unsafe race:ecvt
+T{
+.BR fcvt ()
+T} Thread safety MT-Unsafe race:fcvt
+.TE
+.SH CONFORMING TO
SVr2;
marked as LEGACY in POSIX.1-2001.
-.SH "SEE ALSO"
+POSIX.1-2008 removes the specifications of
+.BR ecvt ()
+and
+.BR fcvt (),
+recommending the use of
+.BR sprintf (3)
+instead (though
+.BR snprintf (3)
+may be preferable).
+.SH NOTES
+.\" Linux libc4 and libc5 specified the type of
+.\" .I ndigits
+.\" as
+.\" .IR size_t .
+Not all locales use a point as the radix character ("decimal point").
+.SH SEE ALSO
.BR ecvt_r (3),
.BR gcvt (3),
.BR qecvt (3),
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