If non-NULL, entry must point to a valid and properly initialised gd_entry_t object, such as that returned by gd_entry(3). As well, the caller may construct a properly initialised gd_entry_t object by first setting all bits to zero, then setting the field_type parameter to the desired gd_entype_t symbol, and finally initialising only the members defined for that type. The results of calling this function are undefined if the character strings pointed to by the string members of entry have not been allocated with malloc(3), unless these pointer members are equal to NULL.

See gd_entry(3) for a description of the gd_entry_t data type.