1Tcl_Panic(3) Tcl Library Procedures Tcl_Panic(3)
2______________________________________________________________________________
6
8 Tcl_Panic, Tcl_PanicVA, Tcl_SetPanicProc, panic, panicVA - report fatal
9 error and abort
10
12 #include <tcl.h>
13 void
15 Tcl_Panic(format, arg, arg, ...)
16 void
18 Tcl_PanicVA(format, argList)
19 void
21 Tcl_SetPanicProc(panicProc)
22 void
24 panic(format, arg, arg, ...)
25 void
27 panicVA(format, argList)
28
31 CONST char* format (in) A printf-style format string.
32 arg (in) Arguments matching the format
34 string.
35 va_list argList (in) An argument list of arguments
37 matching the format string.
38 Must have been initialized using
39 TCL_VARARGS_START, and cleared
40 using va_end.
41 Tcl_PanicProc *panicProc (in) Procedure to report fatal error
43 message and abort.
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46
49 When the Tcl library detects that its internal data structures are in
50 an inconsistent state, or that its C procedures have been called in a
51 manner inconsistent with their documentation, it calls Tcl_Panic to
52 display a message describing the error and abort the process. The for‐
53 mat argument is a format string describing how to format the remaining
54 arguments arg into an error message, according to the same formatting
55 rules used by the printf family of functions. The same formatting
56 rules are also used by the builtin Tcl command format.
57 In a freshly loaded Tcl library, Tcl_Panic prints the formatted error
59 message to the standard error file of the process, and then calls abort
60 to terminate the process. Tcl_Panic does not return.
61 Tcl_SetPanicProc may be used to modify the behavior of Tcl_Panic. The
63 panicProc argument should match the type Tcl_PanicProc:
64 typedef void Tcl_PanicProc(
66 CONST char *format,
67 arg, arg,...);
68 After Tcl_SetPanicProc returns, any future calls to Tcl_Panic will call
70 panicProc, passing along the format and arg arguments. To maintain
71 consistency with the callers of Tcl_Panic, panicProc must not return;
72 it must call abort. panicProc should avoid making calls into the Tcl
73 library, or into other libraries that may call the Tcl library, since
74 the original call to Tcl_Panic indicates the Tcl library is not in a
75 state of reliable operation.
76 The typical use of Tcl_SetPanicProc arranges for the error message to
78 be displayed or reported in a manner more suitable for the application
79 or the platform. As an example, the Windows implementation of wish
80 calls Tcl_SetPanicProc to force all panic messages to be displayed in a
81 system dialog box, rather than to be printed to the standard error file
82 (usually not visible under Windows).
83 Although the primary callers of Tcl_Panic are the procedures of the Tcl
85 library, Tcl_Panic is a public function and may be called by any exten‐
86 sion or application that wishes to abort the process and have a panic
87 message displayed the same way that panic messages from Tcl will be
88 displayed.
89 Tcl_PanicVA is the same as Tcl_Panic except that instead of taking a
91 variable number of arguments it takes an argument list. The procedures
92 panic and panicVA are synonyms (implemented as macros) for Tcl_Panic
93 and Tcl_PanicVA, respectively. They exist to support old code; new
94 code should use direct calls to Tcl_Panic or Tcl_PanicVA.
95
98 abort(3), printf(3), exec(n), format(n)
99
102 abort, fatal, error
103Tcl 8.4 Tcl_Panic(3)