Tcl_CancelEval - cancel Tcl scripts
#include <tcl.h> int Tcl_CancelEval(interp, resultObjPtr, clientData, flags) int Tcl_Canceled(interp, flags)
Tcl_Cancel(3tcl) Tcl Library Procedures Tcl_Cancel(3tcl)
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NAME
Tcl_CancelEval, Tcl_Canceled - cancel Tcl scripts
SYNOPSIS
#include <tcl.h>
int
Tcl_CancelEval(interp, resultObjPtr, clientData, flags)
int
Tcl_Canceled(interp, flags)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter in which to cancel the
script.
Tcl_Obj *resultObjPtr (in) Error message to use in the cancella-
tion, or NULL to use a default mes-
sage. If not NULL, this object will
have its reference count decremented
before Tcl_CancelEval returns.
int flags (in) ORed combination of flag bits that
specify additional options. For
Tcl_CancelEval, only TCL_CANCEL_UNWIND
is currently supported. For Tcl_Can-
celed, only TCL_LEAVE_ERR_MSG and
TCL_CANCEL_UNWIND are currently sup-
ported.
ClientData clientData (in) Currently reserved for future use. It
should be set to NULL.
______________________________________________________________________________
DESCRIPTION
Tcl_CancelEval cancels or unwinds the script in progress soon after the
next invocation of asynchronous handlers, causing TCL_ERROR to be the
return code for that script. This function is thread-safe and may be
called from any thread in the process.
Tcl_Canceled checks if the script in progress has been canceled and
returns TCL_ERROR if it has. Otherwise, TCL_OK is returned. Exten-
sions can use this function to check to see if they should abort a long
running command. This function is thread sensitive and may only be
called from the thread the interpreter was created in.
FLAG BITS
Any ORed combination of the following values may be used for the flags
argument to procedures such as Tcl_CancelEval:
TCL_CANCEL_UNWIND This flag is used by Tcl_CancelEval and Tcl_Can-
celed. For Tcl_CancelEval, if this flag is set,
the script in progress is canceled and the evalua-
tion stack for the interpreter is unwound. For
Tcl_Canceled, if this flag is set, the script in
progress is considered to be canceled only if the
evaluation stack for the interpreter is being
unwound.
TCL_LEAVE_ERR_MSG This flag is only used by Tcl_Canceled; it is
ignored by other procedures. If an error is
returned and this bit is set in flags, then an
error message will be left in the interpreter's
result, where it can be retrieved with Tcl_GetOb-
jResult or Tcl_GetStringResult. If this flag bit
is not set then no error message is left and the
interpreter's result will not be modified.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | runtime/tcl-8 |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
interp(n), Tcl_Eval(3), TIP 285
KEYWORDS
cancel, unwind
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from http://prdownloads.sourceforge.net/tcl/tcl-
core8.6.7-src.tar.gz.
Further information about this software can be found on the open source
community website at https://www.tcl.tk/.
Tcl 8.6 Tcl_Cancel(3tcl)