To write a file or data annotation, the calling program must contain the following routine calls:
C: file_id = Hopen(filename, file_access_mode, num_dds_block);
an_id = ANstart(file_id);
ann_id = ANcreatef(an_id, annot_type);
OR ann_id = ANcreate(an_id, obj_tag, obj_ref, annot_type);
status = ANwriteann(ann_id, ann_text, ann_length);
status = ANendaccess(ann_id);
status = ANend(an_id);
status = Hclose(file_id);
FORTRAN: file_id = hopen(filename, file_access_mode, num_dds_block)
an_id = afstart(file_id)
ann_id = affcreate(an_id, annot_type)
OR ann_id = afcreate(an_id, obj_tag, obj_ref, annot_type)
status = afwriteann(ann_id, ann_text, ann_length)
status = afendaccess(ann_id)
status = afend(an_id)
status = hclose(file_id)
ANwriteann writes the annotation text given in the parameter ann_text to the annotation specified by ann_id. The parameter ann_length specifies the number of characters in the annotation text, not including the NULL character. If the annotation has already been written with text, ANwriteann will overwrite the current text.SUCCEED (or 0) or FAIL (or -1). The parameters of ANwriteann are further defined in Table 10C.
TABLE 10C - ANwriteann Parameter List
In this example, the program creates an HDF file named "General_HDFobjects.hdf" then attaches to it two annotations, a file label and a file description. Within the HDF file, the program creates a vgroup named "AN Vgroup" and attaches to it two annotations, a data label and a data description. Refer to Chapter 5, Vgroups (V API), for a discussion of the V interface routines used in this example.
Note that the names
AN_FILE_LABEL, AN_FILE_DESC, AN_DATA_LABEL, and AN_DATA_DESC are defined by the library to specify the type of the annotation to be accessed.