NAME

       gd_nframes — report the size of a Dirfile

SYNOPSIS

       #include <getdata.h>

       off_t gd_nframes(DIRFILE *dirfile);

DESCRIPTION

       The  gd_nframes()  function queries a dirfile(5) database specified by dirfile and returns
       the number of frames in the database.  Since different fields may have differing number of
       frames,  the  Dirfile  Standards (see dirfile(5)) dictate that the number of frames in the
       database is defined to be equal to the number of frames in the reference field defined  by
       the  /REFERENCE  directive  (see  dirfile-format(5))  or,  if  no  such reference field is
       defined, by the first raw field specified in the format specification.

       If no vector fields are defined in the database, gd_nframes() returns zero and succeeds.

       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_nframes()  returns  the number of frames in the dirfile,
       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_DIRFILE
               The supplied dirfile was invalid.

       GD_E_IO An  I/O  error  occurred  while determining the number of samples in the data file
               associated with the reference field.

       GD_E_UNKNOWN_ENCODING
               The number of samples available for the reference field could  not  be  determined
               because  the  encoding  used  to  store  the  reference  field's data file was not
               understood.

       GD_E_UNSUPPORTED
               GetData does not support determining the number of samples for the encoding of  of
               the data file associated with the reference field.

       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_nframes() function appeared in GetData-0.3.0.

       In GeData-0.7.0, this function was renamed to gd_nframes().

SEE ALSO

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