gd_eof(3) GETDATA gd_eof(3)NAMEgd_eof — report the number of samples in a dirfile field
SYNOPSIS
#include <getdata.h>
off_t gd_eof(DIRFILE *dirfile, const char *field_code);
DESCRIPTION
The gd_eof() function queries a dirfile(5) database specified by
dirfile and returns the sample number of the end-of-field marker for
the vector field given by field_code. This is effectively the total
number of samples available for the field, including any frame offset.
The caller should not assume that this is equivalent (when accounting
for the samples-per-frame of the indicated field) to the number of
frames in the database returned by gd_nframes(3), nor even that the
end-of-field marker falls on a frame boundary.
For a RAW field, the end-of-field marker occurs immediately after the
last datum in the data file associated with the field. For other field
types, the end-of-field marker is equivalent to the end-of-field marker
closest to the start of the dirfile of any of the field inputs. The
special field INDEX has no end-of-field marker.
The end-of-field marker for a field containing no data is in the same
location as, or before, its beginning-of-field marker (see gd_bof(3)).
For a RAW field, the difference between the locations of the beginning-
and end-of-field markers indicates the number of samples of data actu‐
ally stored on disk.
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_eof() returns the sample number of the
end-of-field marker for the indicated field. On error, it returns -1
and sets the dirfile error to a non-zero error value. Possible error
values are:
GD_E_ALLOC
The library was unable to allocate memory.
GD_E_BAD_CODE
The field specified by field_code or one of the fields it uses
as input was not found in the database.
GD_E_BAD_DIRFILE
The supplied dirfile was invalid.
GD_E_BAD_FIELD_TYPE
The location of the non-existent end-of-field marker for the
special field INDEX was requested, possibly as a result of the
field specified by field_code using INDEX as one of its inputs.
GD_E_BAD_REPR
The representation suffix specified in field_code, or in one of
its inputs was not recognised.
GD_E_DIMENSION
A scalar field was found where a vector field was expected in
the definition of field_code or one of its inputs, or else
field_code itself specified a scalar field.
GD_E_INTERNAL_ERROR
An internal error occurred in the library while trying to per‐
form the task. This indicates a bug in the library. Please
report the incident to the GetData developers.
GD_E_RAW_IO
An attempt to stat(2) the file associated with the field, or
one of its input fields, failed.
GD_E_RECURSE_LEVEL
Too many levels of recursion were encountered while trying to
resolve field_code. This usually indicates a circular depen‐
dency in field specification in the dirfile.
GD_E_UNKNOWN_ENCODING
The size of the decoded data file associated with the specified
field or one of its inputs could not be determined, because its
encoding scheme was not understood.
GD_E_UNSUPPORTED
The size of the decoded data file associated with the specified
field or one of its inputs could not be determined, because its
encoding scheme was not supported.
The dirfile error may be retrieved by calling gd_error(3). A descrip‐
tive error string for the last error encountered can be obtained from a
call to gd_error_string(3).
SEE ALSOdirfile(5), dirfile-encoding(5), gd_open(3), gd_bof(3), gd_error(3),
gd_error_string(3), gd_nframes(3)Version 0.8.0 18 August 2011 gd_eof(3)
