NAME¶
Tcl_Panic, Tcl_PanicVA, Tcl_SetPanicProc - report fatal error and abort
SYNOPSIS¶
#include <tcl.h>
void
Tcl_Panic(format, arg, arg, ...)
void
Tcl_PanicVA(format, argList)
void
Tcl_SetPanicProc(panicProc)
ARGUMENTS¶
- const char* format (in)
- A printf-style format string.
- arg (in)
- Arguments matching the format string.
- va_list argList (in)
- An argument list of arguments matching the format string. Must have been
initialized using va_start, and cleared using va_end.
- Tcl_PanicProc *panicProc (in)
- Procedure to report fatal error message and abort.
DESCRIPTION¶
When the Tcl library detects that its internal data structures are in an
inconsistent state, or that its C procedures have been called in a manner
inconsistent with their documentation, it calls
Tcl_Panic to display a
message describing the error and abort the process. The
format argument
is a format string describing how to format the remaining arguments
arg
into an error message, according to the same formatting rules used by the
printf family of functions. The same formatting rules are also used by
the built-in Tcl command
format.
In a freshly loaded Tcl library,
Tcl_Panic prints the formatted error
message to the standard error file of the process, and then calls
abort
to terminate the process.
Tcl_Panic 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.
wish.exe), then a system dialog box is used to display the panic
message.
Tcl_SetPanicProc may be used to modify the behavior of
Tcl_Panic.
The
panicProc argument should match the type
Tcl_PanicProc:
typedef void Tcl_PanicProc(
const char * format,
arg, arg,...);
After
Tcl_SetPanicProc returns, any future calls to
Tcl_Panic will
call
panicProc, passing along the
format and
arg
arguments.
panicProc should avoid making calls into the Tcl library, or
into other libraries that may call the Tcl library, since the original call to
Tcl_Panic indicates the Tcl library is not in a state of reliable
operation.
The typical use of
Tcl_SetPanicProc arranges for the error message to be
displayed or reported in a manner more suitable for the application or the
platform.
Although the primary callers of
Tcl_Panic are the procedures of the Tcl
library,
Tcl_Panic 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.
Tcl_PanicVA is the same as
Tcl_Panic except that instead of taking
a variable number of arguments it takes an argument list.
SEE ALSO¶
abort(3),
printf(3), exec(3tcl), format(3tcl)
KEYWORDS¶
abort, fatal, error