Descriptor for variable-length text.

typedef struct _UMATextDescr {
  uint32     offset;  /*  Offset to beginning of data. */
  uint32     count;   /*  Count of elements in the text. */
} UMATextDescr;

typedef   UMATextDescr   * UMATextDescr ;

Support for random access to variable-length members of structures requires that the address of these members is derived from fixed size structures at known offsets within the main structure definition. There are 3 types of variable length member descriptor structures, all of which contain the offset required to locate the variable-length data. The 'offset' is considered relative to the base address of the parent structure of the variable-length member descriptor. Extra information concerning the variable length data may also be available.

Note that it is not possible to determine whether a variable-length data has been initialized before it is referenced. As a convention, setting the offset and count to 0 could be used to indicate an uninitialized variable-length data item.


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