Tcl Source Code

2011-08-14  Jan Nijtmans  <[email protected]>

	* doc/FindExec.3: [Patch 3124554]: Move WishPanic from Tk to Tcl
	* doc/Panic.3     Added Documentation

2011-08-12  Don Porter  <[email protected]>

	* generic/tclPathObj.c:	[Bug 3389764] Eliminate possibility that dup
	of a "path" value can create reference cycle.

2011-08-12  Donal K. Fellows  <[email protected]>

\fIargv[0]\fR as its argument.  It is important not to change the
working directory before the invocation.
\fBTcl_FindExecutable\fR uses \fIargv0\fR
along with the \fBPATH\fR environment variable to find the
application's executable, if possible.  If it fails to find
the binary, then future calls to \fBinfo nameofexecutable\fR
will return an empty string.
.PP
On Windows platforms this procedure is typically invoked as the very
first thing in the application's main program as well; Its \fIargv[0]\fR
argument is only used to indicate wheter the executable has a stderr
channel (any non-null value) or not (the value null). If \fBTcl_SetPanicProc\fR
is never called and no debugger is running, this determines whether
the panic message is sent to stderr or to a standard system dialog.
.PP
\fBTcl_GetNameOfExecutable\fR simply returns a pointer to the
internal full path name of the executable file as computed by
\fBTcl_FindExecutable\fR.  This procedure call is the C API
equivalent to the \fBinfo nameofexecutable\fR command.  NULL
is returned if the internal full path name has not been
computed or unknown.

same formatting rules used by the \fBprintf\fR family of functions.  The
same formatting rules are also used by the built-in Tcl command
\fBformat\fR.
.PP
In a freshly loaded Tcl library, \fBTcl_Panic\fR prints the formatted
error message to the standard error file of the process, and then
calls \fBabort\fR to terminate the process.  \fBTcl_Panic\fR does not
return. On Windows, when a debugger is running, the formatted error
message is sent to the debugger in stead. If the windows executable
does not have a stderr channel (e.g. \fBwish.exe\fR), then a
system dialog box is used to display the panic message.
.PP
\fBTcl_SetPanicProc\fR may be used to modify the behavior of
\fBTcl_Panic\fR.  The \fIpanicProc\fR argument should match the
type \fBTcl_PanicProc\fR:
.PP
.CS
typedef void \fBTcl_PanicProc\fR(
        const char *\fBformat\fR,
        \fBarg\fR, \fBarg\fR,...);
.CE
.PP
After \fBTcl_SetPanicProc\fR returns, any future calls to
\fBTcl_Panic\fR will call \fIpanicProc\fR, passing along the
\fIformat\fR and \fIarg\fR arguments. \fIpanicProc\fR should avoid


making calls into the Tcl library, or into other libraries that may
call the Tcl library, since the original call to \fBTcl_Panic\fR
indicates the Tcl library is not in a state of reliable operation.  
.PP
The typical use of \fBTcl_SetPanicProc\fR arranges for the error message
to be displayed or reported in a manner more suitable for the
application or the platform.



.PP
Although the primary callers of \fBTcl_Panic\fR are the procedures of
the Tcl library, \fBTcl_Panic\fR is a public function and may be called
by any extension or application that wishes to abort the process and
have a panic message displayed the same way that panic messages from Tcl
will be displayed.
.PP