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Tcl_Panic(3tcl) Tcl Library Procedures Tcl_Panic(3tcl) 


NAME

Tcl_Panic, Tcl_PanicVA, Tcl_SetPanicProc, panic, panicVA - report fatal error
  and abort

SYNOPSIS


#include <tcl.h>

 

void
Tcl_Panic(format, arg, arg, ...)

 

void
Tcl_PanicVA(format, argList)

 

void
Tcl_SetPanicProc(panicProc)

 

void
panic(format, arg, arg, ...)

 

void
panicVA(format, argList)

 




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 TCL_VARARGS_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 builtin 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.


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. To maintain consistency with the callers of Tcl_Panic,
  panicProc must not return; it must call abort. 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. As an example, the Windows implementation of wish calls
  Tcl_SetPanicProc to force all panic messages to be displayed in a
  system dialog box, rather than to be printed to the standard error file
  (usually not visible under Windows).


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. The procedures
  panic and panicVA are synonyms (implemented as macros) for
  Tcl_Panic and Tcl_PanicVA, respectively. They exist to support
  old code; new code should use direct calls to Tcl_Panic or
  Tcl_PanicVA.

 


SEE ALSO

abort(3), printf(3), exec(3tcl), format(3tcl)

 


KEYWORDS

abort, fatal, error

 





  

    8.4
    Tcl