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 associ‐
       ated 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  begin‐
       ning-of-field  marker  (see gd_bof(3)).  For a RAW field, the difference between the locations of the be‐
       ginning- 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  indi‐
       cated field.  On error, it returns -1 and sets the dirfile error to a non-zero error value.  Possible er‐
       ror 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)

Version 0.9.0                                    16 October 2014                                       gd_eof(3)