NAME

       gd_frameoffset — report the starting frame of fields in a Dirfile

SYNOPSIS

       #include <getdata.h>

       off_t gd_frameoffset(DIRFILE *dirfile, int fragment_index);

DESCRIPTION

       The  gd_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  frag‐
       ment  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 ig‐
       nored.

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

RETURN VALUE

       Upon successful completion, gd_frameoffset() returns a non-negative integer containing the  frame  offset
       of the specified fragment.  On error, it returns a negative-valued error code.  Possible error codes are:

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_INDEX
               The supplied index was out of range.

       The  error  code is also stored in the DIRFILE object and may be retrieved after this function returns by
       calling  gd_error(3).   A  descriptive  error  string  for  the  error  may  be   obtained   by   calling
       gd_error_string(3).

HISTORY

       The get_frameoffset() function appeared in GetData-0.5.0.

       In GetData-0.7.0, this function was renamed to gd_frameoffset().

       In GetData-0.10.0, the error return from this function changed from -1 to a negative-valued error code.

SEE ALSO

       gd_alter_frameoffset(3), gd_error(3), gd_error_string(3), gd_open(3), dirfile(5), dirfile-format(5)

Version 0.10.0                                  25 December 2016                               gd_frameoffset(3)