plucky (3) gd_nframes.3.gz

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)