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Tcl_GetIndexFromObj(3)Tcl Library ProcedureTcl_GetIndexFromObj(3)
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Tcl_GetIndexFromObj - lookup string in table of keywords
#include <tcl.h>
int
Tcl_GetIndexFromObj(interp, objPtr, tablePtr, msg, flags, indexPtr)
Tcl_Interp *interp (in) Interpreter to use for
error reporting; if
NULL, then no message
is provided on errors.
Tcl_Obj *objPtr (in/out) The string value of
this object is used to
search through
tablePtr. The inter
nal representation is
modified to hold the
index of the matching
table entry.
char **tablePtr (in) An array of null-ter
minated strings. The
end of the array is
marked by a NULL
string pointer.
char *msg (in) Null-terminated string
describing what is
being looked up, such
as option. This
string is included in
error messages.
int flags (in) OR-ed combination of
bits providing addi
tional information for
operation. The only
bit that is currently
defined is TCL_EXACT.
int *indexPtr (out) The index of the
string in tablePtr
that matches the value
of objPtr is returned
here.
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Tcl_GetIndexFromObj(3)Tcl Library ProcedureTcl_GetIndexFromObj(3)
This procedure provides an efficient way for looking up
keywords, switch names, option names, and similar things
where the value of an object must be one of a predefined
set of values. ObjPtr is compared against each of the
strings in tablePtr to find a match. A match occurs if
objPtr's string value is identical to one of the strings
in tablePtr, or if it is a unique abbreviation for exactly
one of the strings in tablePtr and the TCL_EXACT flag was
not specified; in either case the index of the matching
entry is stored at *indexPtr and TCL_OK is returned.
If there is no matching entry, TCL_ERROR is returned and
an error message is left in interp's result if interp
isn't NULL. Msg is included in the error message to indi
cate what was being looked up. For example, if msg is
option the error message will have a form like bad option
"firt": must be first, second, or third.
If Tcl_GetIndexFromObj completes successfully it modifies
the internal representation of objPtr to hold the address
of the table and the index of the matching entry. If
Tcl_GetIndexFromObj is invoked again with the same objPtr
and tablePtr arguments (e.g. during a reinvocation of a
Tcl command), it returns the matching index immediately
without having to redo the lookup operation. Note:
Tcl_GetIndexFromObj assumes that the entries in tablePtr
are static: they must not change between invocations.
Tcl_WrongNumArgs
index, object, table lookup
Tcl 8.0 2 | 
