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   1 '\" te

   2 .\" Copyright (c) 2014 Gary Mills
   3 .\" Copyright (c) 2008, Sun Microsystems, Inc.  All Rights Reserved.
   4 .\" Copyright 1989 AT&T
   5 .\" Portions Copyright (c) 1992, X/Open Company Limited.  All Rights Reserved.
   6 .\" 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
   7 .\" http://www.opengroup.org/bookstore/.
   8 .\" 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.
   9 .\"  This notice shall appear on any product containing this material.
  10 .\" 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.
  11 .\" 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.
  12 .\" 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]
  13 .TH STRFTIME 3C "Jan 3, 2014"
  14 .SH NAME
  15 strftime, strftime_l cftime, ascftime \- convert date and time to string
  16 .SH SYNOPSIS
  17 .LP
  18 .nf
  19 #include <time.h>
  20 
  21 \fBsize_t\fR \fBstrftime\fR(\fBchar *restrict\fR \fIs\fR, \fBsize_t\fR \fImaxsize\fR,
  22      \fBconst char *restrict\fR \fIformat\fR,
  23      \fBconst struct tm *restrict\fR \fItimeptr\fR);



  24 \fBsize_t\fR \fBstrftime_l\fR(\fBchar *restrict\fR \fIs\fR, \fBsize_t\fR \fImaxsize\fR,
  25      \fBconst char *restrict\fR \fIformat\fR,
  26      \fBconst struct tm *restrict\fR \fItimeptr\fR, \fBlocale_t\fR \fIloc\fR);
  27 .fi
  28 
  29 .LP
  30 .nf
  31 \fBint\fR \fBcftime\fR(\fBchar *\fR\fIs\fR, \fBchar *\fR\fIformat\fR, \fBconst time_t *\fR\fIclock\fR);
  32 .fi
  33 
  34 .LP
  35 .nf
  36 \fBint\fR \fBascftime\fR(\fBchar *\fR\fIs\fR, \fBconst char *\fR\fIformat\fR,
  37      \fBconst struct tm *\fR\fItimeptr\fR);
  38 .fi
  39 
  40 .SH DESCRIPTION
  41 .sp
  42 .LP
  43 The \fBstrftime()\fR, \fBascftime()\fR, and \fBcftime()\fR functions place

  44 bytes into the array pointed to by \fIs\fR as controlled by the string pointed
  45 to by \fIformat\fR. The \fIformat\fR string consists of zero or more conversion
  46 specifications and ordinary characters.  A conversion specification consists of
  47 a '\fB%\fR' (percent) character and one or two terminating conversion
  48 characters that determine the conversion specification's behavior.  All
  49 ordinary characters (including the terminating null byte) are copied unchanged
  50 into the array pointed to by \fIs\fR. If copying takes place between objects
  51 that overlap, the behavior is undefined. For \fBstrftime()\fR, no more than
  52 \fImaxsize\fR bytes are placed into the array. The \fBstrftime_l()\fR function
  53 behaves identically to \fBstrftime()\fR function, but instead of operating in
  54 the current locale, it operates in the locale specified by \fIloc\fR.
  55 .sp
  56 .LP
  57 If \fIformat\fR is \fB(char *)0\fR, then the locale's default format is used.
  58 For \fBstrftime()\fR the default format is the same as \fB%c\fR; for
  59 \fBcftime()\fR and \fBascftime()\fR the default format is the same as \fB%+\fR.
  60 \fBcftime()\fR and \fBascftime()\fR first try to use the value of the
  61 environment variable \fBCFTIME\fR, and if that is undefined or empty, the
  62 default format is used.
  63 .sp
  64 .LP
  65 Each conversion specification is replaced by appropriate characters as
  66 described in the following list. The appropriate characters are determined by
  67 the \fBLC_TIME\fR category of the program's locale and by the values contained
  68 in the structure pointed to by \fItimeptr\fR for \fBstrftime()\fR and
  69 \fBascftime()\fR, and by the time represented by \fIclock\fR for
  70 \fBcftime()\fR.
  71 .sp
  72 .ne 2
  73 .na
  74 \fB\fB%%\fR\fR
  75 .ad
  76 .RS 6n
  77 Same as \fB%\fR.
  78 .RE
  79 
  80 .sp
  81 .ne 2
  82 .na
  83 \fB\fB%a\fR\fR


 453 .RE
 454 
 455 .sp
 456 .ne 2
 457 .na
 458 \fB\fB%Z\fR\fR
 459 .ad
 460 .RS 6n
 461 Time zone name or abbreviation, or no bytes if no time zone information exists.
 462 .RE
 463 
 464 .sp
 465 .ne 2
 466 .na
 467 \fB\fB%+\fR\fR
 468 .ad
 469 .RS 6n
 470 Locale's date and time representation as produced by \fBdate\fR(1).
 471 .RE
 472 
 473 .sp
 474 .LP
 475 If a conversion specification does not correspond to any of the above or to any
 476 of the modified conversion specifications listed below, the behavior is
 477 undefined and \fB0\fR is returned.
 478 .sp
 479 .LP
 480 The difference between \fB%U\fR and \fB%W\fR (and also between modified
 481 conversion specifications \fB%OU\fR and \fB%OW\fR) lies in which day is counted
 482 as the first of the week. Week number 1 is the first week in January starting
 483 with a Sunday for \fB%U\fR or a Monday for \fB%W\fR. Week number 0 contains
 484 those days before the first Sunday or Monday in January for \fB%U\fR and
 485 \fB%W\fR, respectively.
 486 .SS "Modified Conversion Specifications"
 487 .sp
 488 .LP
 489 Some conversion specifications can be modified by the \fBE\fR and \fBO\fR
 490 modifiers to indicate that an alternate format or specification should be used
 491 rather than the one normally used by the unmodified conversion specification.
 492 If the alternate format or specification does not exist in the current locale,
 493 the behavior will be as if the unmodified specification were used.
 494 .sp
 495 .ne 2
 496 .na
 497 \fB\fB%Ec\fR\fR
 498 .ad
 499 .RS 7n
 500 Locale's alternate appropriate date and time representation.
 501 .RE
 502 
 503 .sp
 504 .ne 2
 505 .na
 506 \fB\fB%EC\fR\fR
 507 .ad


 669 .ne 2
 670 .na
 671 \fB\fB%OW\fR\fR
 672 .ad
 673 .RS 7n
 674 Week number of the year (Monday as the first day of the week) using the
 675 locale's alternate numeric symbols.
 676 .RE
 677 
 678 .sp
 679 .ne 2
 680 .na
 681 \fB\fB%Oy\fR\fR
 682 .ad
 683 .RS 7n
 684 Year (offset from \fB%C\fR) in the locale's alternate representation and using
 685 the locale's alternate numeric symbols.
 686 .RE
 687 
 688 .SS "Selecting the Output Language"
 689 .sp
 690 .LP
 691 By default, the output of \fBstrftime()\fR, \fBcftime()\fR, and
 692 \fBascftime()\fR appear in U.S. English. The user can request that the output
 693 of \fBstrftime()\fR, \fBcftime()\fR, or \fBascftime()\fR be in a specific
 694 language by setting the \fBLC_TIME\fR category using \fBsetlocale()\fR.
 695 .SS "Time Zone"
 696 .sp
 697 .LP
 698 Local time zone information is used as though \fBtzset\fR(3C) were called.
 699 .SH RETURN VALUES
 700 .sp
 701 .LP
 702 The \fBstrftime()\fR, \fBcftime()\fR, and \fBascftime()\fR functions return the
 703 number of characters placed into the array pointed to by \fIs\fR, not including
 704 the terminating null character. If the total number of resulting characters
 705 including the terminating null character is more than \fImaxsize\fR,
 706 \fBstrftime()\fR returns \fB0\fR and the contents of the array are
 707 indeterminate.
 708 .SH EXAMPLES
 709 .LP
 710 \fBExample 1 \fRAn example of the \fBstrftime()\fR function.
 711 .sp
 712 .LP
 713 The following example illustrates the use of \fBstrftime()\fR for the
 714 \fBPOSIX\fR locale. It shows what the string in \fIstr\fR would look like if
 715 the structure pointed to by \fItmptr\fR contains the values corresponding to
 716 Thursday, August 28, 1986 at 12:44:36.
 717 
 718 .sp
 719 .in +2
 720 .nf
 721 \fBstrftime (str, strsize, "%A %b %d %j", tmptr)\fR

 722 .fi
 723 .in -2
 724 
 725 .sp
 726 .LP
 727 This results in \fIstr\fR containing "Thursday Aug 28 240".
 728 
 729 .SH ATTRIBUTES
 730 .sp
 731 .LP
 732 See \fBattributes\fR(5) for descriptions of the following attributes:
 733 .sp
 734 
 735 .sp
 736 .TS
 737 box;
 738 c | c
 739 l | l .
 740 ATTRIBUTE TYPE  ATTRIBUTE VALUE
 741 _
 742 CSI     Enabled
 743 _
 744 Interface Stability     Committed
 745 _
 746 MT-Level        MT-Safe
 747 _
 748 Standard        See below.
 749 .TE
 750 
 751 .sp
 752 .LP
 753 For \fBstrftime()\fR, see \fBstandards\fR(5).



 754 .SH SEE ALSO
 755 .sp
 756 .LP
 757 \fBdate\fR(1), \fBctime\fR(3C), \fBmktime\fR(3C), \fBsetlocale\fR(3C),
 758 \fBstrptime\fR(3C), \fBtzset\fR(3C), \fBTIMEZONE\fR(4), \fBzoneinfo\fR(4),

 759 \fBattributes\fR(5), \fBenviron\fR(5), \fBstandards\fR(5)
 760 .SH NOTES
 761 .sp
 762 .LP
 763 The conversion specification for \fB%V\fR was changed in the Solaris 7 release.
 764 This change was based on the public review draft of the ISO C9x standard at
 765 that time. Previously, the specification stated that if the week containing 1
 766 January had fewer than four days in the new year, it became week 53 of the
 767 previous year. The ISO C9x standard committee subsequently recognized that that
 768 specification had been incorrect.
 769 .sp
 770 .LP
 771 The conversion specifications for \fB%g\fR, \fB%G\fR, \fB%Eg\fR, \fB%EG\fR, and
 772 \fB%Og\fR were added in the Solaris 7 release.  This change was based on the
 773 public review draft of the ISO C9x standard at that time. These specifications
 774 are evolving.  If the ISO C9x standard is finalized with a different
 775 conclusion, these specifications will change to conform to the ISO C9x standard
 776 decision.
 777 .sp
 778 .LP
 779 The conversion specification for \fB%u\fR was changed in the Solaris 8 release.
 780 This change was based on the XPG4 specification.
 781 .sp
 782 .LP
 783 If using the \fB%Z\fR specifier and \fBzoneinfo\fR timezones and if the input
 784 date is outside the range 20:45:52 UTC, December  13, 1901 to 03:14:07 UTC,
 785 January 19, 2038, the timezone name may not be correct.
 786 .sp
 787 .LP
 788 The conversion specification for \fB%+\fR was added in illumos.
 789 It is not part of any standard, although it is available on a number
 790 of other platforms.
 791 Its use is discouraged for conforming applications.
   1 '\" te
   2 .\" Copyright 2014 Garrett D'Amore <garrett@damore.org>
   3 .\" Copyright (c) 2014 Gary Mills
   4 .\" Copyright (c) 2008, Sun Microsystems, Inc.  All Rights Reserved.
   5 .\" Copyright 1989 AT&T
   6 .\" Portions Copyright (c) 1992, X/Open Company Limited.  All Rights Reserved.
   7 .\" 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
   8 .\" http://www.opengroup.org/bookstore/.
   9 .\" 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.
  10 .\"  This notice shall appear on any product containing this material.
  11 .\" 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.
  12 .\" 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.
  13 .\" 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]
  14 .TH STRFTIME 3C "Jun 24, 2014"
  15 .SH NAME
  16 strftime, strftime_l cftime, ascftime \- convert date and time to string
  17 .SH SYNOPSIS
  18 .LP
  19 .nf
  20 #include <time.h>
  21 
  22 \fBsize_t\fR \fBstrftime\fR(\fBchar *restrict\fR \fIs\fR, \fBsize_t\fR \fImaxsize\fR,
  23      \fBconst char *restrict\fR \fIformat\fR,
  24      \fBconst struct tm *restrict\fR \fItimeptr\fR);
  25 .fi
  26 .LP
  27 .nf
  28 \fBsize_t\fR \fBstrftime_l\fR(\fBchar *restrict\fR \fIs\fR, \fBsize_t\fR \fImaxsize\fR,
  29      \fBconst char *restrict\fR \fIformat\fR,
  30      \fBconst struct tm *restrict\fR \fItimeptr\fR, \fBlocale_t\fR \fIloc\fR);
  31 .fi

  32 .LP
  33 .nf
  34 \fBint\fR \fBcftime\fR(\fBchar *\fR\fIs\fR, \fBchar *\fR\fIformat\fR, \fBconst time_t *\fR\fIclock\fR);
  35 .fi

  36 .LP
  37 .nf
  38 \fBint\fR \fBascftime\fR(\fBchar *\fR\fIs\fR, \fBconst char *\fR\fIformat\fR,
  39      \fBconst struct tm *\fR\fItimeptr\fR);
  40 .fi
  41 
  42 .SH DESCRIPTION
  43 .sp
  44 .LP
  45 The \fBstrftime()\fR, \fBstrftime_l()\fR, \fBascftime()\fR, and \fBcftime()\fR
  46 functions place
  47 bytes into the array pointed to by \fIs\fR as controlled by the string pointed
  48 to by \fIformat\fR. The \fIformat\fR string consists of zero or more conversion
  49 specifications and ordinary characters.  A conversion specification consists of
  50 a '\fB%\fR' (percent) character and one or two terminating conversion
  51 characters that determine the conversion specification's behavior.  All
  52 ordinary characters (including the terminating null byte) are copied unchanged
  53 into the array pointed to by \fIs\fR. If copying takes place between objects
  54 that overlap, the behavior is undefined. For \fBstrftime()\fR, no more than
  55 \fImaxsize\fR bytes are placed into the array. The \fBstrftime_l()\fR function
  56 behaves identically to \fBstrftime()\fR function, but instead of operating in
  57 the current locale, it operates in the locale specified by \fIloc\fR.

  58 .LP
  59 If \fIformat\fR is \fB(char *)0\fR, then the locale's default format is used.
  60 For \fBstrftime()\fR the default format is the same as \fB%c\fR; for
  61 \fBcftime()\fR and \fBascftime()\fR the default format is the same as \fB%+\fR.
  62 \fBcftime()\fR and \fBascftime()\fR first try to use the value of the
  63 environment variable \fBCFTIME\fR, and if that is undefined or empty, the
  64 default format is used.

  65 .LP
  66 Each conversion specification is replaced by appropriate characters as
  67 described in the following list. The appropriate characters are determined by
  68 the \fBLC_TIME\fR category of the program's locale and by the values contained
  69 in the structure pointed to by \fItimeptr\fR for \fBstrftime()\fR and
  70 \fBascftime()\fR, and by the time represented by \fIclock\fR for
  71 \fBcftime()\fR.
  72 .sp
  73 .ne 2
  74 .na
  75 \fB\fB%%\fR\fR
  76 .ad
  77 .RS 6n
  78 Same as \fB%\fR.
  79 .RE
  80 
  81 .sp
  82 .ne 2
  83 .na
  84 \fB\fB%a\fR\fR


 454 .RE
 455 
 456 .sp
 457 .ne 2
 458 .na
 459 \fB\fB%Z\fR\fR
 460 .ad
 461 .RS 6n
 462 Time zone name or abbreviation, or no bytes if no time zone information exists.
 463 .RE
 464 
 465 .sp
 466 .ne 2
 467 .na
 468 \fB\fB%+\fR\fR
 469 .ad
 470 .RS 6n
 471 Locale's date and time representation as produced by \fBdate\fR(1).
 472 .RE
 473 

 474 .LP
 475 If a conversion specification does not correspond to any of the above or to any
 476 of the modified conversion specifications listed below, the behavior is
 477 undefined and \fB0\fR is returned.

 478 .LP
 479 The difference between \fB%U\fR and \fB%W\fR (and also between modified
 480 conversion specifications \fB%OU\fR and \fB%OW\fR) lies in which day is counted
 481 as the first of the week. Week number 1 is the first week in January starting
 482 with a Sunday for \fB%U\fR or a Monday for \fB%W\fR. Week number 0 contains
 483 those days before the first Sunday or Monday in January for \fB%U\fR and
 484 \fB%W\fR, respectively.
 485 .SS "Modified Conversion Specifications"

 486 .LP
 487 Some conversion specifications can be modified by the \fBE\fR and \fBO\fR
 488 modifiers to indicate that an alternate format or specification should be used
 489 rather than the one normally used by the unmodified conversion specification.
 490 If the alternate format or specification does not exist in the current locale,
 491 the behavior will be as if the unmodified specification were used.
 492 .sp
 493 .ne 2
 494 .na
 495 \fB\fB%Ec\fR\fR
 496 .ad
 497 .RS 7n
 498 Locale's alternate appropriate date and time representation.
 499 .RE
 500 
 501 .sp
 502 .ne 2
 503 .na
 504 \fB\fB%EC\fR\fR
 505 .ad


 667 .ne 2
 668 .na
 669 \fB\fB%OW\fR\fR
 670 .ad
 671 .RS 7n
 672 Week number of the year (Monday as the first day of the week) using the
 673 locale's alternate numeric symbols.
 674 .RE
 675 
 676 .sp
 677 .ne 2
 678 .na
 679 \fB\fB%Oy\fR\fR
 680 .ad
 681 .RS 7n
 682 Year (offset from \fB%C\fR) in the locale's alternate representation and using
 683 the locale's alternate numeric symbols.
 684 .RE
 685 
 686 .SS "Selecting the Output Language"

 687 .LP
 688 These routines produce output that is formatted according to the \fBLC_TIME\fR
 689 locale category.  They use either the current locale, or in the case of
 690 \fBstrftime_l()\fR, the locale supplied by \fIloc\fR.

 691 .SS "Time Zone"

 692 .LP
 693 Local time zone information is used as though \fBtzset\fR(3C) were called.
 694 .SH RETURN VALUES

 695 .LP
 696 These functions return the
 697 number of characters placed into the array pointed to by \fIs\fR, not including
 698 the terminating null character. If the total number of resulting characters
 699 including the terminating null character is more than \fImaxsize\fR,
 700 \fBstrftime()\fR returns \fB0\fR and the contents of the array are
 701 indeterminate.
 702 .SH EXAMPLES
 703 .LP
 704 \fBExample 1 \fRAn example of the \fBstrftime()\fR function.

 705 .LP
 706 The following example illustrates the use of \fBstrftime()\fR for the
 707 \fBPOSIX\fR locale. It shows what the string in \fIstr\fR would look like if
 708 the structure pointed to by \fItmptr\fR contains the values corresponding to
 709 Thursday, August 28, 1986 at 12:44:36.



 710 .nf
 711 .IP
 712 \fBstrftime\fR(\fIstr\fR, \fIstrsize\fR, "%A %b %d %j", \fItmptr\fR);
 713 .fi



 714 .LP
 715 This results in \fIstr\fR containing "Thursday Aug 28 240".

 716 .SH ATTRIBUTES

 717 .LP
 718 See \fBattributes\fR(5) for descriptions of the following attributes:



 719 .TS
 720 box;
 721 c | c
 722 l | l .
 723 ATTRIBUTE TYPE  ATTRIBUTE VALUE
 724 _
 725 CSI     Enabled
 726 _
 727 Interface Stability     See below.
 728 _
 729 MT-Level        MT-Safe
 730 _
 731 Standard        See below.
 732 .TE
 733 

 734 .LP
 735 The \fBstrftime()\fR and \fBstrftime_l()\fR functions are Standard.
 736 \fBcftime()\fR and \fBascftime()\fR functions are Committed.
 737 .LP
 738 For \fBstrftime()\fR and \fBstrftime_l()\fR, see \fBstandards\fR(5).
 739 .SH SEE ALSO

 740 .LP
 741 \fBdate\fR(1), \fBctime\fR(3C), \fBmktime\fR(3C),
 742 \fBnewlocale\fR(3C), \fBsetlocale\fR(3C), \fBstrptime\fR(3C), \fBtzset\fR(3C),
 743 \fBuselocale\fR(3C), \fBTIMEZONE\fR(4), \fBzoneinfo\fR(4),
 744 \fBattributes\fR(5), \fBenviron\fR(5), \fBstandards\fR(5)
 745 .SH NOTES

 746 .LP
 747 The conversion specification for \fB%V\fR was changed in the Solaris 7 release.
 748 This change was based on the public review draft of the ISO C9x standard at
 749 that time. Previously, the specification stated that if the week containing 1
 750 January had fewer than four days in the new year, it became week 53 of the
 751 previous year. The ISO C9x standard committee subsequently recognized that that
 752 specification had been incorrect.

 753 .LP
 754 The conversion specifications for \fB%g\fR, \fB%G\fR, \fB%Eg\fR, \fB%EG\fR, and
 755 \fB%Og\fR were added in the Solaris 7 release.  This change was based on the
 756 public review draft of the ISO C9x standard at that time. The \fB%g\fR and
 757 \fB%G\fR specifications were adopted in the formal standard.  The other two
 758 were not, and should not be used in portable applications.


 759 .LP
 760 The conversion specification for \fB%u\fR was changed in the Solaris 8 release.
 761 This change was based on the XPG4 specification.

 762 .LP
 763 If using the \fB%Z\fR specifier and \fBzoneinfo\fR timezones and if the input
 764 date is outside the range 20:45:52 UTC, December  13, 1901 to 03:14:07 UTC,
 765 January 19, 2038, the timezone name may not be correct.

 766 .LP
 767 The conversion specification for \fB%+\fR was added in illumos.
 768 It is not part of any standard, although it is available on a number
 769 of other platforms.
 770 Its use is discouraged for conforming applications.