NAME

       XtConvertAndStore, XtCallConverter - invoke resource converters

SYNTAX

       #include <X11/Intrinsic.h>

       Boolean XtConvertAndStore(Widget widget, const char *from_type, XrmValuePtr from, const
              char *to_type, XrmValuePtr to_in_out);

       Boolean XtCallConverter(Display* dpy, XtTypeConverter converter, XrmValuePtr args,
              Cardinal num_args, XrmValuePtr from, XrmValuePtr to_in_out, XtCacheRef*
              cache_ref_return);

ARGUMENTS

       args      Specifies the argument list that contains the additional arguments needed to
                 perform the conversion, or NULL.

       converter Specifies the conversion procedure that is to be called.

       from      Specifies the value to be converted.

       from_type Specifies the source type.

       num_args  Specifies the number of additional arguments (often zero).

       to_type   Specifies the destination type.

       to_in_out Returns the converted value.

       widget    Specifies the widget to use for additional arguments, if any are needed, and the
                 destroy callback list.

       dpy       Specifies the display with which the conversion is to be associated.

DESCRIPTION

       The XtConvertAndStore function looks up the type converter registered to convert from_type
       to to_type, computes any additional arguments needed, and then calls XtCallConverter.  (or
       XtDirectConvert if an old-style converter was registered with XtAddConverter or
       XtAppAddConverter.  ) with the from and to_in_out arguments.

       The XtCallConverter function looks up the specified type converter in the application
       context associated with the display and, if the converter was not registered or was
       registered with cache type XtCacheAll or XtCacheByDisplay looks in the conversion cache to
       see if this conversion procedure has been called with the specified conversion arguments.
       If so, it checks the success status of the prior call, and if the conversion failed,
       XtCallConverter returns False immediately; otherwise it checks the size specified in the
       to argument and, if it is greater than or equal to the size stored in the cache, copies
       the information stored in the cache into the location specified by to->addr, stores the
       cache size into to->size, and returns True.  If the size specified in the to argument is
       smaller than the size stored in the cache, XtCallConverter copies the cache size into the
       to->size and returns False.  If the converter was registered with cache type XtCacheNone
       or no value was found in the conversion cache, XtCallConverter calls the converter and, if
       it was not registered with cache type XtCacheNone, enters the result into the cache.
       XtCallConverter then returns what the converter returned.

       The cache_ref_return field specifies storage allocated by the caller in which an opaque
       value will be stored.  If the type converter has been registered with the XtCacheRefCount
       modifier and if the value returned in in cache_ref_return is non-NULL, then the call
       should store the cache_ref_return value in order to decrement the reference count when the
       converted value is no longer required.  The cache_ref_return argument should be NULL if
       the caller is unwilling or unable to store the value.

SEE ALSO

       XtAppReleaseCacheRefs(3)
       X Toolkit Intrinsics - C Language Interface
       Xlib - C Language X Interface