get_frameoffset (3) - Linux Manuals

get_frameoffset: report the starting frame of fields in a dirfile


get_frameoffset --- report the starting frame of fields in a dirfile


#include <getdata.h>
off_t get_frameoffset(DIRFILE *dirfile, int fragment_index);


The get_frameoffset() function queries a dirfile(5) database specified by dirfile and returns the frame offset (see dirfile-format(5)) for the fragment indexed by fragment_index. The frame offset of a fragment indicate the frame number of the first sample of data stored in binary files associated with RAW fields defined in the specified fragment. The frame offset of a fragment containing no RAW fields is ignored.

The dirfile argument must point to a valid DIRFILE object previously created by a call to dirfile_open(3).


Upon successful completion, get_frameoffset() returns the frame offset of the specified fragment. On error, it returns -1 and sets the dirfile error to a non-zero error value. Possible error values are:
The supplied dirfile was invalid.
The supplied index was out of range. The dirfile error may be retrieved by calling get_error(3). A descriptive error string for the last error encountered can be obtained from a call to get_error_string(3).