gd_tell — report the position of a Dirfile field I/O pointer

       The  gd_tell()  function  reports  the current position of the I/O pointer of the field field_code in the
       dirfile(5) database specified by dirfile.

       Only RAW fields (and the implicit INDEX  field)  have  field  pointers  associated  with  them.   Calling
       gd_tell() on a derived field will report the position of the I/O pointer of the derived field only if all
       of it's inputs are positioned the same.  Otherwise, an error results.

       The gd_tell() function appeared in GetData-0.8.0.

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

       gd_tell — report the position of a Dirfile field I/O pointer

       Upon  successful  completion, gd_tell() returns a non-negative integer indicating the I/O position of the
       specified field in samples.  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 for input, was not found in the
               database.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_DIMENSION
               The specified field or one of its inputs wasn't of vector type.

       GD_E_DOMAIN
               The I/O position of a derived field wasn't well defined because its input  fields  simultaneously
               read from different places in the same RAW 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 maintainer.

       GD_E_IO An error occurred while trying to open or read from a file on disk containing a raw field.

       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 encoding scheme of a RAW field could not be determined.  This may also indicate that the  bi‐
               nary file associated with the RAW field could not be found.

       GD_E_UNSUPPORTED
               Reading  from  dirfiles with the encoding scheme of the specified dirfile is not supported by the
               library.  See dirfile-encoding(5) for details on dirfile encoding schemes.

       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).

gd_getdata(3), gd_open(3), gd_putdata(3), gd_seek(3).

Version 0.10.0                                  25 December 2016                                      gd_tell(3)

#include<getdata.h>off_tgd_tell(DIRFILE*dirfile,constchar*field_code);