Tcl Library Procedures                            TclPanic(3TCL)





NAME
     TclPanic, TclPanicVA, TclSetPanicProc, panic,  panicVA  -
     report fatal error and abort

SYNOPSIS
     #include 

     void
     TclPanic(format, arg, arg, ...)

     void
     TclPanicVA(format, argList)

     void
     TclSetPanicProc(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.

     valist         argList      (in)      An argument  list  of
                                            arguments    matching
                                            the  format   string.
                                            Must  have  been ini-
                                            tialized        using
                                            TCLVARARGSTART,
                                            and   cleared   using
                                            vaend.

     TclPanicProc   *panicProc   (in)      Procedure  to  report
                                            fatal  error  message
                                            and abort.




DESCRIPTION
     When the Tcl library detects that its internal  data  struc-
     tures are in an inconsistent state, or that its C procedures
     have  been  called  in  a  manner  inconsistent  with  their



Tcl                     Last change: 8.4                        1






Tcl Library Procedures                            TclPanic(3TCL)



     documentation,  it  calls  TclPanic  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 func-
     tions.  The same formatting rules are also used by the buil-
     tin Tcl command format.

     In a freshly loaded Tcl library, TclPanic prints  the  for-
     matted  error message to the standard error file of the pro-
     cess,  and  then  calls  abort  to  terminate  the  process.
     TclPanic does not return.

     TclSetPanicProc may be  used  to  modify  the  behavior  of
     TclPanic.   The  panicProc  argument  should match the type
     TclPanicProc:

          typedef void TclPanicProc(
            CONST char *format,
            arg, arg,...);

     After  TclSetPanicProc  returns,  any   future   calls   to
     TclPanic  will call panicProc, passing along the format and
     arg arguments.  To maintain consistency with the callers  of
     TclPanic,  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 TclPanic indicates the Tcl library  is
     not in a state of reliable operation.

     The typical use of TclSetPanicProc arranges for  the  error
     message  to  be displayed or reported in a manner more suit-
     able for the application or the platform.   As  an  example,
     the Windows implementation of wish calls TclSetPanicProc 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 TclPanic are the procedures
     of  the  Tcl library, TclPanic 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.

     TclPanicVA is the same as TclPanic except that instead  of
     taking  a  variable number of arguments it takes an argument
     list.  The procedures panic and panicVA are synonyms (imple-
     mented  as  macros)  for  TclPanic and TclPanicVA, respec-
     tively.  They exist to support old code; new code should use
     direct calls to TclPanic or TclPanicVA.





Tcl                     Last change: 8.4                        2






Tcl Library Procedures                            TclPanic(3TCL)



SEE ALSO
     abort(3TCL), printf(3TCL), exec(1T), format(1T)


KEYWORDS
     abort, fatal, error


ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     
       ATRIBUTE TYPE     ATRIBUTE VALUE
    
     Availability         SUNWTcl        
    
     Interface Stability  Uncommitted    
    

NOTES
     Source for Tcl is available on http:/opensolaris.org.

































Tcl                     Last change: 8.4                        3