Tk_GetAnchorFromObj(3) Tk Library Procedures Tk_GetAnchorFromObj(3)
Tk_GetAnchorFromObj, Tk_GetAnchor, Tk_NameOfAnchor - translate between strings and anchor
Tk_GetAnchorFromObj(interp, objPtr, anchorPtr)
Tk_GetAnchor(interp, string, anchorPtr)
const char *
Tcl_Interp *interp (in) Interpreter to use for error reporting, or NULL.
Tcl_Obj *objPtr (in/out) String value contains name of anchor point: "n", "ne",
"e", "se", "s", "sw", "w", "nw", or "center"; internal
rep will be modified to cache corresponding Tk_Anchor.
const char *string (in) Same as objPtr except description of anchor point is
passed as a string.
int *anchorPtr (out) Pointer to location in which to store anchor position
corresponding to objPtr or string.
Tk_Anchor anchor (in) Anchor position, e.g. TCL_ANCHOR_CENTER.
Tk_GetAnchorFromObj places in *anchorPtr an anchor position (enumerated type Tk_Anchor)
corresponding to objPtr's value. The result will be one of TK_ANCHOR_N, TK_ANCHOR_NE,
TK_ANCHOR_E, TK_ANCHOR_SE, TK_ANCHOR_S, TK_ANCHOR_SW, TK_ANCHOR_W, TK_ANCHOR_NW, or
TK_ANCHOR_CENTER. Anchor positions are typically used for indicating a point on an object
that will be used to position the object, e.g. TK_ANCHOR_N means position the top center
point of the object at a particular place.
Under normal circumstances the return value is TCL_OK and interp is unused. If string
does not contain a valid anchor position or an abbreviation of one of these names,
TCL_ERROR is returned, *anchorPtr is unmodified, and an error message is stored in
interp's result if interp is not NULL. Tk_GetAnchorFromObj caches information about the
return value in objPtr, which speeds up future calls to Tk_GetAnchorFromObj with the same
Tk_GetAnchor is identical to Tk_GetAnchorFromObj except that the description of the anchor
is specified with a string instead of an object. This prevents Tk_GetAnchor from caching
the return value, so Tk_GetAnchor is less efficient than Tk_GetAnchorFromObj.
Tk_NameOfAnchor is the logical inverse of Tk_GetAnchor. Given an anchor position such as
TK_ANCHOR_N it returns a statically-allocated string corresponding to anchor. If anchor
is not a legal anchor value, then "unknown anchor position" is returned.
Tk 8.1 Tk_GetAnchorFromObj(3)