'\" '\" Copyright (c) 2001 by Kevin B. Kenny . '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" .TH Tcl_GetTime 3tcl 8.4 Tcl "Tcl Library Procedures" .\" The -*- nroff -*- definitions below are for supplemental macros used .\" in Tcl/Tk manual entries. .\" .\" .AP type name in/out ?indent? .\" Start paragraph describing an argument to a library procedure. .\" type is type of argument (int, etc.), in/out is either "in", "out", .\" or "in/out" to describe whether procedure reads or modifies arg, .\" and indent is equivalent to second arg of .IP (shouldn't ever be .\" needed; use .AS below instead) .\" .\" .AS ?type? ?name? .\" Give maximum sizes of arguments for setting tab stops. Type and .\" name are examples of largest possible arguments that will be passed .\" to .AP later. If args are omitted, default tab stops are used. .\" .\" .BS .\" Start box enclosure. From here until next .BE, everything will be .\" enclosed in one large box. .\" .\" .BE .\" End of box enclosure. .\" .\" .CS .\" Begin code excerpt. .\" .\" .CE .\" End code excerpt. .\" .\" .VS ?version? ?br? .\" Begin vertical sidebar, for use in marking newly-changed parts .\" of man pages. The first argument is ignored and used for recording .\" the version when the .VS was added, so that the sidebars can be .\" found and removed when they reach a certain age. If another argument .\" is present, then a line break is forced before starting the sidebar. .\" .\" .VE .\" End of vertical sidebar. .\" .\" .DS .\" Begin an indented unfilled display. .\" .\" .DE .\" End of indented unfilled display. .\" .\" .SO ?manpage? .\" Start of list of standard options for a Tk widget. The manpage .\" argument defines where to look up the standard options; if .\" omitted, defaults to "options". The options follow on successive .\" lines, in three columns separated by tabs. .\" .\" .SE .\" End of list of standard options for a Tk widget. .\" .\" .OP cmdName dbName dbClass .\" Start of description of a specific option. cmdName gives the .\" option's name as specified in the class command, dbName gives .\" the option's name in the option database, and dbClass gives .\" the option's class in the option database. .\" .\" .UL arg1 arg2 .\" Print arg1 underlined, then print arg2 normally. .\" .\" .QW arg1 ?arg2? .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). .\" .\" .PQ arg1 ?arg2? .\" Print an open parenthesis, arg1 in quotes, then arg2 normally .\" (for trailing punctuation) and then a closing parenthesis. .\" .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b .\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. .\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out .\" # BS - start boxed text .\" # ^y = starting y location .\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. .\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. .\" # VS - start vertical sidebar .\" # ^Y = starting y location .\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. .\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. .\" # Special macro to handle page bottom: finish off current .\" # box/sidebar if in box/sidebar mode, then invoked standard .\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. .\" # DS - begin display .de DS .RS .nf .sp .. .\" # DE - end display .de DE .fi .RE .sp .. .\" # SO - start of list of standard options .de SO 'ie '\\$1'' .ds So \\fBoptions\\fR 'el .ds So \\fB\\$1\\fR .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. .\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\*(So manual entry for details on the standard options. .. .\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. .\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. .\" # CE - end code excerpt .de CE .fi .RE .. .\" # UL - underline word .de UL \\$1\l'|0\(ul'\\$2 .. .\" # QW - apply quotation marks to word .de QW .ie '\\*(lq'"' ``\\$1''\\$2 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\$2 .. .\" # PQ - apply parens and quotation marks to word .de PQ .ie '\\*(lq'"' (``\\$1''\\$2)\\$3 .\"" fix emacs highlighting .el (\\*(lq\\$1\\*(rq\\$2)\\$3 .. .\" # QR - quoted range .de QR .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 .. .\" # MT - "empty" string .de MT .QW "" .. .BS .SH NAME Tcl_GetTime, Tcl_SetTimeProc, Tcl_QueryTimeProc \- get date and time .SH SYNOPSIS .nf \fB#include \fR .sp \fBTcl_GetTime\fR(\fItimePtr\fR) .sp \fBTcl_SetTimeProc\fR(\fIgetProc, scaleProc, clientData\fR) .sp \fBTcl_QueryTimeProc\fR(\fIgetProcPtr, scaleProcPtr, clientDataPtr\fR) .SH ARGUMENTS .AS Tcl_GetTimeProc *getProc in .AP Tcl_Time *timePtr out Points to memory in which to store the date and time information. .AP Tcl_GetTimeProc getProc in Pointer to handler function replacing \fBTcl_GetTime\fR's access to the OS. .AP Tcl_ScaleTimeProc scaleProc in Pointer to handler function for the conversion of time delays in the virtual domain to real-time. .AP ClientData clientData in Value passed through to the two handler functions. .AP Tcl_GetTimeProc *getProcPtr out Pointer to place the currently registered get handler function into. .AP Tcl_ScaleTimeProc *scaleProcPtr out Pointer to place the currently registered scale handler function into. .AP ClientData *clientDataPtr out Pointer to place the currently registered pass-through value into. .BE .SH DESCRIPTION .PP The \fBTcl_GetTime\fR function retrieves the current time as a \fITcl_Time\fR structure in memory the caller provides. This structure has the following definition: .PP .CS typedef struct Tcl_Time { long \fIsec\fR; long \fIusec\fR; } \fBTcl_Time\fR; .CE .PP On return, the \fIsec\fR member of the structure is filled in with the number of seconds that have elapsed since the \fIepoch:\fR the epoch is the point in time of 00:00 UTC, 1 January 1970. This number does \fInot\fR count leap seconds \- an interval of one day advances it by 86400 seconds regardless of whether a leap second has been inserted. .PP The \fIusec\fR member of the structure is filled in with the number of microseconds that have elapsed since the start of the second designated by \fIsec\fR. The Tcl library makes every effort to keep this number as precise as possible, subject to the limitations of the computer system. On multiprocessor variants of Windows, this number may be limited to the 10- or 20-ms granularity of the system clock. (On single-processor Windows systems, the \fIusec\fR field is derived from a performance counter and is highly precise.) .SS "VIRTUALIZED TIME" .PP The \fBTcl_SetTimeProc\fR function registers two related handler functions with the core. The first handler function is a replacement for \fBTcl_GetTime\fR, or rather the OS access made by \fBTcl_GetTime\fR. The other handler function is used by the Tcl notifier to convert wait/block times from the virtual domain into real time. .PP The \fBTcl_QueryTimeProc\fR function returns the currently registered handler functions. If no external handlers were set then this will return the standard handlers accessing and processing the native time of the OS. The arguments to the function are allowed to be NULL; and any argument which is NULL is ignored and not set. .PP The signatures of the handler functions are as follows: .PP .CS typedef void \fBTcl_GetTimeProc\fR( Tcl_Time *\fItimebuf\fR, ClientData \fIclientData\fR); typedef void \fBTcl_ScaleTimeProc\fR( Tcl_Time *\fItimebuf\fR, ClientData \fIclientData\fR); .CE .PP The \fItimebuf\fR fields contain the time to manipulate, and the \fIclientData\fR fields contain a pointer supplied at the time the handler functions were registered. .PP Any handler pair specified has to return data which is consistent between them. In other words, setting one handler of the pair to something assuming a 10-times slowdown, and the other handler of the pair to something assuming a two-times slowdown is wrong and not allowed. .PP The set handler functions are allowed to run the delivered time backwards, however this should be avoided. We have to allow it as the native time can run backwards as the user can fiddle with the system time one way or other. Note that the insertion of the hooks will not change the behavior of the Tcl core with regard to this situation, i.e. the existing behavior is retained. .SH "SEE ALSO" clock(3tcl) .SH KEYWORDS date, time