NAME

       gd_eof — find the end of 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 determines 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.  The special field INDEX has no end-of-field marker.

       The end-of-field of a PHASE field is the end-of-field of its input adjusted by the PHASE  field's  shift.
       For  other  vector field types, the end-of-field marker is the smallest end-of-field marker of any of its
       inputs.

       If the end-of-field marker for a field is less than  or  equal  to  its  beginning-of-field  marker  (see
       gd_bof(3)), then that field has no data.  For a RAW field, the difference between the beginning- and end-
       of-field markers indicates the number of samples of data actually 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,  which is never negative.  On error, it returns a negative-valued error code.  Possible
       error codes 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_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 perform the task.  This indicates a bug
               in the library.  Please report the incident to the GetData developers.

       GD_E_IO An I/O error occurred while deterimining the size of the raw data file associated with the field,
               or one of its input fields.

       GD_E_RECURSE_LEVEL
               Too  many  levels of recursion were encountered while trying to resolve field_code.  This usually
               indicates a circular dependency 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 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 gd_eof() function appeared in GetData-0.7.0.

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

SEE ALSO

       gd_bof(3), gd_error(3), gd_error_string(3), gd_nframes(3), gd_open(3), dirfile(5), dirfile-encoding(5)