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.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified Sat Jul 24 19:40:39 1993 by Rik Faith (faith@cs.unc.edu)
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.\" Modified Fri Jun 25 12:10:47 1999 by Andries Brouwer (aeb@cwi.nl)
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.\"
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2009-03-14 18:19:36 +00:00
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.TH ECVT 3 2009-03-15 "" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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ecvt, fcvt \- convert a floating-point number to a string
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.SH SYNOPSIS
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.B #include <stdlib.h>
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.sp
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.BI "char *ecvt(double " number ", int " ndigits ", int *" decpt ,
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.BI "int *" sign );
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.sp
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.BI "char *fcvt(double " number ", int " ndigits ", int *" decpt ,
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.BI "int *" sign );
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2007-07-08 12:11:40 +00:00
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.sp
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.in -4n
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.in
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.sp
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.BR ecvt (),
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.BR fcvt ():
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_SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500
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.SH DESCRIPTION
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2007-05-12 09:06:04 +00:00
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The
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.BR ecvt ()
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function converts \fInumber\fP to a null-terminated
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2007-12-29 18:01:05 +00:00
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string of \fIndigits\fP digits (where \fIndigits\fP is reduced to a
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2007-12-18 07:52:55 +00:00
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system-specific limit determined by the precision of a
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.IR double ),
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and returns a pointer to the string.
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intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
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The high-order digit is nonzero, unless
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.I number
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is zero.
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The low order digit is rounded.
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2004-11-03 13:51:07 +00:00
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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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2007-12-22 21:40:53 +00:00
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is stored in \fI*decpt\fP.
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A negative value for \fI*decpt\fP means that
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2007-04-12 22:42:49 +00:00
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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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intro.1, time.1, adjtimex.2, capget.2, eventfd.2, fcntl.2, getrlimit.2, getsockopt.2, gettimeofday.2, intro.2, ioctl_list.2, ioperm.2, mlock.2, pivot_root.2, poll.2, prctl.2, ptrace.2, sched_setscheduler.2, select_tut.2, semget.2, sigaltstack.2, signalfd.2, sysctl.2, timer_settime.2, timerfd_create.2, wait.2, CPU_SET.3, argz_add.3, assert_perror.3, atexit.3, backtrace.3, bcmp.3, clearenv.3, ctime.3, dl_iterate_phdr.3, dlopen.3, ecvt.3, errno.3, error.3, ether_aton.3, exit.3, fenv.3, ferror.3, finite.3, flockfile.3, fnmatch.3, fpathconf.3, fpclassify.3, ftime.3, ftok.3, ftw.3, fwide.3, getaddrinfo.3, gethostbyname.3, getlogin.3, getnameinfo.3, getnetent.3, getopt.3, getprotoent.3, getrpcent.3, getservent.3, glob.3, hsearch.3, inet.3, isalpha.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, longjmp.3, lsearch.3, malloc.3, matherr.3, mblen.3, mbsinit.3, mbtowc.3, on_exit.3, printf.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_equal.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedparam.3, pthread_setschedprio.3, ptsname.3, putenv.3, putgrent.3, raise.3, rcmd.3, regex.3, rexec.3, rpc.3, rpmatch.3, rtnetlink.3, scandir.3, sem_init.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, signbit.3, stdio_ext.3, strtod.3, strtol.3, strtoul.3, system.3, termios.3, timeradd.3, tzset.3, ualarm.3, wctomb.3, xdr.3, st.4, tty_ioctl.4, core.5, elf.5, proc.5, bootparam.7, capabilities.7, icmp.7, ip.7, ipv6.7, math_error.7, mdoc.samples.7, mq_overview.7, pthreads.7, raw.7, regex.7, socket.7, tcp.7, tzselect.8: Global fix: s/non-zero/nonzero/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:40:55 +00:00
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\fInumber\fP is negative, \fI*sign\fP is set to a nonzero value,
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2007-06-02 05:45:14 +00:00
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otherwise it is set to 0.
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2007-04-12 22:42:49 +00:00
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If
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2004-11-03 13:51:07 +00:00
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.I number
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2007-12-22 21:40:53 +00:00
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is zero, it is unspecified whether \fI*decpt\fP is 0 or 1.
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2004-11-03 13:51:07 +00:00
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.PP
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2007-05-12 09:06:04 +00:00
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The
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.BR fcvt ()
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function is identical to
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.BR ecvt (),
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except that
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2004-11-03 13:51:07 +00:00
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\fIndigits\fP specifies the number of digits after the decimal point.
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.SH "RETURN VALUE"
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2007-05-12 09:06:04 +00:00
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Both the
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.BR ecvt ()
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and
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.BR fcvt ()
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functions return a pointer to a
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2004-11-03 13:51:07 +00:00
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static string containing the ASCII representation of \fInumber\fP.
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2007-05-12 09:06:04 +00:00
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The static string is overwritten by each call to
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.BR ecvt ()
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or
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.BR fcvt ().
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2007-05-19 04:30:20 +00:00
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.SH "CONFORMING TO"
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SVr2;
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marked as LEGACY in POSIX.1-2001.
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2008-08-06 12:06:23 +00:00
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POSIX.1-2008 removes the specifications of
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.BR ecvt ()
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and
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2009-03-14 18:19:36 +00:00
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.BR fcvt (),
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recommending the use of
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2007-05-12 00:30:29 +00:00
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.BR sprintf (3)
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2009-03-14 18:19:36 +00:00
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instead (though
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.BR snprintf (3)
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may be preferable).
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.SH NOTES
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2004-11-03 13:51:07 +00:00
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Linux libc4 and libc5 specified the type of
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.I ndigits
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as
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2007-06-23 07:56:56 +00:00
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.IR size_t .
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2007-12-18 07:47:22 +00:00
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Not all locales use a point as the radix character ("decimal point").
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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.BR ecvt_r (3),
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.BR gcvt (3),
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.BR qecvt (3),
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.BR setlocale (3),
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.BR sprintf (3)
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