NAME
XtAllocateGC - obtain a sharable GC with modifiable fields
SYNTAX
GC XtAllocateGC(Widget w, Cardinal depth, XtGCMask
value_mask, XGCValues *values, XtGCMask dynamic_mask,
XtGCMask unused_mask);
ARGUMENTS
values
Specifies the actual values for this GC.
value_mask
Specifies which .
w
Specifies the widget.
depth
Specifies the depth for which the returned GC is valid, or 0.
Specifies the fields of the GC that will be modified by the caller.
Specifies the fields of the GC that will not be needed by the caller.
DESCRIPTION
The
function returns a sharable GC that may be modified by the client.
The screen field of the specified widget or of the nearest
widget ancestor of the specified object and the specified depth
argument supply the root and drawable depths for which the GC is to
be valid. If depth is zero the depth is taken from the depth
field of the specified widget or of the nearest widget ancestor of the
specified object.
The value_mask argument specifies the fields of the GC that will
be initialized with the respective members of the values structure.
The dynamic_mask argument specifies fields that the caller intends
to modify during program execution. The caller must ensure that the
corresponding GC field is set prior to each use of the GC. The
unused_mask argument specifies fields of the GC that are of no
interest to the caller. The caller may make no assumptions about the
contents of any fields specified in unused_mask. The caller may
assume that at all times all fields not specified in either
dynamic_mask or unused_mask have their default value if
not specified in value_mask or the value specified by values.
If a field is specified in both value_mask and dynamic_mask,
the effect is as if it were specified only in dynamic_mask and
then immediately set to the value in values. If a field is set
in unused_mask and also in either value_mask or
dynamic_mask, the specification in unused_mask is ignored.
tries to minimize the number of unique GCs created by comparing the
arguments with those of previous calls and returning an existing GC
when there are no conflicts.
may modify and return an existing GC if it was allocated with a nonzero
unused_mask.
SEE ALSO
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