gd_frameoffset - Man Page
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 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 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)
Referenced By
gd_alter_frameoffset(3), gd_bof(3), gd_framenum_subset(3), gd_frameoffset64(3).