HPUX CrtTrace[3]
CrtTrace in anderen Kapiteln des hpux Handbuch:
Tcl_CreateTrace(3) Tcl Tcl_CreateTrace(3)
Tcl Library Procedures Tcl Library Procedures
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NAME
Tcl_CreateTrace, Tcl_DeleteTrace - arrange for command execution to be
traced
SYNOPSIS
#include <tcl.h>
Tcl_Trace
Tcl_CreateTrace(interp, level, proc, clientData)
Tcl_DeleteTrace(interp, trace)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter containing
command to be traced or
untraced.
int level (in) Only commands at or
below this nesting level
will be traced. 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.
Tcl_CmdTraceProc *proc (in) Procedure to call for
each command that's
executed. See below for
details on the calling
sequence.
ClientData clientData (in) Arbitrary one-word value
to pass to proc.
Tcl_Trace trace (in) Token for trace to be
removed (return value
from previous call to
Tcl_CreateTrace).
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- 1 - Formatted: August 11, 1996
Tcl_CreateTrace(3) Tcl Tcl_CreateTrace(3)
Tcl Library Procedures Tcl Library Procedures
DESCRIPTION
Tcl_CreateTrace arranges for command tracing. From now on, proc will
be invoked before Tcl calls command procedures to process commands in
interp. The return value from Tcl_CreateTrace is a token for the
trace, which may be passed to Tcl_DeleteTrace to remove the trace.
There may be many traces in effect simultaneously for the same command
interpreter.
Proc should have arguments and result that match the type
Tcl_CmdTraceProc:
typedef void Tcl_CmdTraceProc(
ClientData clientData,
Tcl_Interp *interp,
int level,
char *command,
Tcl_CmdProc *cmdProc,
ClientData cmdClientData,
int argc,
char *argv[]));
The clientData and interp parameters are copies of the corresponding
arguments given to Tcl_CreateTrace. ClientData typically points to an
application-specific data structure that describes what to do when
proc is invoked. Level gives the nesting level of the command (1 for
top-level commands passed to Tcl_Eval by the application, 2 for the
next-level commands passed to Tcl_Eval as part of parsing or
interpreting level-1 commands, and so on). Command points to a string
containing the text of the command, before any argument substitution.
CmdProc contains the address of the command procedure that will be
called to process the command (i.e. the proc argument of some previous
call to Tcl_CreateCommand) and cmdClientData contains the associated
client data for cmdProc (the clientData value passed to
Tcl_CreateCommand). Argc and argv give the final argument information
that will be passed to cmdProc, after command, variable, and backslash
substitution. Proc must not modify the command or argv strings.
Tracing will only occur for commands at nesting level less than or
equal to the level parameter (i.e. the level parameter to proc will
always be less than or equal to the level parameter to
Tcl_CreateTrace).
Calls to proc will be made by the Tcl parser immediately before it
calls the command procedure for the command (cmdProc). 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
- 2 - Formatted: August 11, 1996
Tcl_CreateTrace(3) Tcl Tcl_CreateTrace(3)
Tcl Library Procedures Tcl Library Procedures
contains multiple commands (bracketed, or on different lines) then
multiple calls to proc will occur, one for each command. The command
string for each of these trace calls will reflect only a single
command, not the entire string passed to Tcl_Eval.
Tcl_DeleteTrace removes a trace, so that no future calls will be made
to the procedure associated with the trace. After Tcl_DeleteTrace
returns, the caller should never again use the trace token.
KEYWORDS
command, create, delete, interpreter, trace
- 3 - Formatted: August 11, 1996