+++ /dev/null
-'\"
-'\" Copyright (c) 1989-1993 The Regents of the University of California.
-'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
-'\" Copyright (c) 2002 by Kevin B. Kenny <kennykb@acm.org>. All rights reserved.
-'\"
-'\" See the file "license.terms" for information on usage and redistribution
-'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\"
-.TH Tcl_CreateTrace 3 "" Tcl "Tcl Library Procedures"
-.so man.macros
-.BS
-.SH NAME
-Tcl_CreateTrace, Tcl_CreateObjTrace, Tcl_DeleteTrace \- arrange for command execution to be traced
-.SH SYNOPSIS
-.nf
-\fB#include <tcl.h>\fR
-.sp
-Tcl_Trace
-\fBTcl_CreateTrace\fR(\fIinterp, level, proc, clientData\fR)
-.sp
-Tcl_Trace
-\fBTcl_CreateObjTrace\fR(\fIinterp, level, flags, objProc, clientData, deleteProc\fR)
-.sp
-\fBTcl_DeleteTrace\fR(\fIinterp, trace\fR)
-.SH ARGUMENTS
-.AS Tcl_CmdObjTraceDeleteProc *deleteProc
-.AP Tcl_Interp *interp in
-Interpreter containing command to be traced or untraced.
-.AP int level in
-Only commands at or below this nesting level will be traced unless
-0 is specified. 1 means
-top-level commands only, 2 means top-level commands or those that are
-invoked as immediate consequences of executing top-level commands
-(procedure bodies, bracketed commands, etc.) and so on.
-A value of 0 means that commands at any level are traced.
-.AP int flags in
-Flags governing the trace execution. See below for details.
-.AP Tcl_CmdObjTraceProc *objProc in
-Procedure to call for each command that is executed. See below for
-details of the calling sequence.
-.AP Tcl_CmdTraceProc *proc in
-Procedure to call for each command that is executed. See below for
-details on the calling sequence.
-.AP ClientData clientData in
-Arbitrary one-word value to pass to \fIobjProc\fR or \fIproc\fR.
-.AP Tcl_CmdObjTraceDeleteProc *deleteProc in
-Procedure to call when the trace is deleted. See below for details of
-the calling sequence. A NULL pointer is permissible and results in no
-callback when the trace is deleted.
-.AP Tcl_Trace trace in
-Token for trace to be removed (return value from previous call
-to \fBTcl_CreateTrace\fR).
-.BE
-.SH DESCRIPTION
-.PP
-\fBTcl_CreateObjTrace\fR arranges for command tracing. After it is
-called, \fIobjProc\fR will be invoked before the Tcl interpreter calls
-any command procedure when evaluating commands in \fIinterp\fR.
-The return value from \fBTcl_CreateObjTrace\fR is a token for the trace,
-which may be passed to \fBTcl_DeleteTrace\fR to remove the trace.
-There may be many traces in effect simultaneously for the same
-interpreter.
-.PP
-\fIobjProc\fR should have arguments and result that match the type,
-\fBTcl_CmdObjTraceProc\fR:
-.PP
-.CS
-typedef int \fBTcl_CmdObjTraceProc\fR(
- \fBClientData\fR \fIclientData\fR,
- \fBTcl_Interp\fR* \fIinterp\fR,
- int \fIlevel\fR,
- const char *\fIcommand\fR,
- \fBTcl_Command\fR \fIcommandToken\fR,
- int \fIobjc\fR,
- \fBTcl_Obj\fR *const \fIobjv\fR[]);
-.CE
-.PP
-The \fIclientData\fR and \fIinterp\fR parameters are copies of the
-corresponding arguments given to \fBTcl_CreateTrace\fR.
-\fIClientData\fR typically points to an application-specific data
-structure that describes what to do when \fIobjProc\fR is invoked. The
-\fIlevel\fR parameter gives the nesting level of the command (1 for
-top-level commands passed to \fBTcl_Eval\fR by the application, 2 for
-the next-level commands passed to \fBTcl_Eval\fR as part of parsing or
-interpreting level-1 commands, and so on). The \fIcommand\fR parameter
-points to a string containing the text of the command, before any
-argument substitution. The \fIcommandToken\fR parameter is a Tcl
-command token that identifies the command to be invoked. The token
-may be passed to \fBTcl_GetCommandName\fR,
-\fBTcl_GetCommandInfoFromToken\fR, or \fBTcl_SetCommandInfoFromToken\fR to
-manipulate the definition of the command. The \fIobjc\fR and \fIobjv\fR
-parameters designate the final parameter count and parameter vector
-that will be passed to the command, and have had all substitutions
-performed.
-.PP
-The \fIobjProc\fR callback is expected to return a standard Tcl status
-return code. If this code is \fBTCL_OK\fR (the normal case), then
-the Tcl interpreter will invoke the command. Any other return code
-is treated as if the command returned that status, and the command is
-\fInot\fR invoked.
-.PP
-The \fIobjProc\fR callback must not modify \fIobjv\fR in any way. It
-is, however, permissible to change the command by calling
-\fBTcl_SetCommandTokenInfo\fR prior to returning. Any such change
-takes effect immediately, and the command is invoked with the new
-information.
-.PP
-Tracing will only occur for commands at nesting level less than
-or equal to the \fIlevel\fR parameter (i.e. the \fIlevel\fR
-parameter to \fIobjProc\fR will always be less than or equal to the
-\fIlevel\fR parameter to \fBTcl_CreateTrace\fR).
-.PP
-Tracing has a significant effect on runtime performance because it
-causes the bytecode compiler to refrain from generating in-line code
-for Tcl commands such as \fBif\fR and \fBwhile\fR in order that they
-may be traced. If traces for the built-in commands are not required,
-the \fIflags\fR parameter may be set to the constant value
-\fBTCL_ALLOW_INLINE_COMPILATION\fR. In this case, traces on built-in
-commands may or may not result in trace callbacks, depending on the
-state of the interpreter, but run-time performance will be improved
-significantly. (This functionality is desirable, for example, when
-using \fBTcl_CreateObjTrace\fR to implement an execution time
-profiler.)
-.PP
-Calls to \fIobjProc\fR will be made by the Tcl parser immediately before
-it calls the command procedure for the command (\fIcmdProc\fR). This
-occurs after argument parsing and substitution, so tracing for
-substituted commands occurs before tracing of the commands
-containing the substitutions. If there is a syntax error in a
-command, or if there is no command procedure associated with a
-command name, then no tracing will occur for that command. If a
-string passed to Tcl_Eval contains multiple commands (bracketed, or
-on different lines) then multiple calls to \fIobjProc\fR will occur,
-one for each command.
-.PP
-\fBTcl_DeleteTrace\fR removes a trace, so that no future calls will be
-made to the procedure associated with the trace. After \fBTcl_DeleteTrace\fR
-returns, the caller should never again use the \fItrace\fR token.
-.PP
-When \fBTcl_DeleteTrace\fR is called, the interpreter invokes the
-\fIdeleteProc\fR that was passed as a parameter to
-\fBTcl_CreateObjTrace\fR. The \fIdeleteProc\fR must match the type,
-\fBTcl_CmdObjTraceDeleteProc\fR:
-.PP
-.CS
-typedef void \fBTcl_CmdObjTraceDeleteProc\fR(
- \fBClientData\fR \fIclientData\fR);
-.CE
-.PP
-The \fIclientData\fR parameter will be the same as the
-\fIclientData\fR parameter that was originally passed to
-\fBTcl_CreateObjTrace\fR.
-.PP
-\fBTcl_CreateTrace\fR is an alternative interface for command tracing,
-\fInot recommended for new applications\fR. It is provided for backward
-compatibility with code that was developed for older versions of the
-Tcl interpreter. It is similar to \fBTcl_CreateObjTrace\fR, except
-that its \fIproc\fR parameter should have arguments and result that
-match the type \fBTcl_CmdTraceProc\fR:
-.PP
-.CS
-typedef void \fBTcl_CmdTraceProc\fR(
- ClientData \fIclientData\fR,
- Tcl_Interp *\fIinterp\fR,
- int \fIlevel\fR,
- char *\fIcommand\fR,
- Tcl_CmdProc *\fIcmdProc\fR,
- ClientData \fIcmdClientData\fR,
- int \fIargc\fR,
- const char *\fIargv\fR[]);
-.CE
-.PP
-The parameters to the \fIproc\fR callback are similar to those of the
-\fIobjProc\fR callback above. The \fIcommandToken\fR is
-replaced with \fIcmdProc\fR, a pointer to the (string-based) command
-procedure that will be invoked; and \fIcmdClientData\fR, the client
-data that will be passed to the procedure. The \fIobjc\fR parameter
-is replaced with an \fIargv\fR parameter, that gives the arguments to
-the command as character strings.
-\fIProc\fR must not modify the \fIcommand\fR or \fIargv\fR strings.
-.PP
-If a trace created with \fBTcl_CreateTrace\fR is in effect, inline
-compilation of Tcl commands such as \fBif\fR and \fBwhile\fR is always
-disabled. There is no notification when a trace created with
-\fBTcl_CreateTrace\fR is deleted.
-There is no way to be notified when the trace created by
-\fBTcl_CreateTrace\fR is deleted. There is no way for the \fIproc\fR
-associated with a call to \fBTcl_CreateTrace\fR to abort execution of
-\fIcommand\fR.
-.SH KEYWORDS
-command, create, delete, interpreter, trace
OSDN Git Service
