Tk_GetAnchorFromObj(3) Tk Library Procedures Tk_GetAnchorFromObj(3)

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NAME

Tk_GetAnchorFromObj, Tk_GetAnchor, Tk_NameOfAnchor - translate
between strings and anchor positions

SYNOPSIS

#include <tk.h>

int
Tk_GetAnchorFromObj(interp, objPtr, anchorPtr)

int
Tk_GetAnchor(interp, string, anchorPtr)

const char *
Tk_NameOfAnchor(anchor)

ARGUMENTS

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. In the case of "center"
on input, a non-empty abbreviation
of it may also be used on input.

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.
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DESCRIPTION

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 objPtr.

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.

KEYWORDS

anchor position

Tk 8.1 Tk_GetAnchorFromObj(3)