NAME

       gd_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 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.  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_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 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 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 dirfile error may be retrieved by calling gd_error(3).  A descriptive error string for the last error
       encountered can be obtained from a call to gd_error_string(3).

SEE ALSO

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