Tcl_Panic
Section: Tcl Library Procedures (3)
Updated: 8.4
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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
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const char* format (in)
A print-style format string.
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arg (in)
Arguments matching the format string.
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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.
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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 buil-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 instead. 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:
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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(n),
format(n)
KEYWORDS
abort, fatal, error
Index
- NAME
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- SYNOPSIS
-
- ARGUMENTS
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- DESCRIPTION
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- SEE ALSO
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- KEYWORDS
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