NCL Home > Documentation > Functions > File IO


Reads binary records written by a Fortran direct access write or C write.


	function fbindirread (
		path     [1] : string,           
		rec_num  [1] : integer,          
		rec_dims [*] : integer or long,  
		rec_type [1] : string            

	return_val [rec_dims] :  rec_type



Pathname to binary file


Record number to read from the file beginning at 0. Please see caveat below.


A singly dimensioned array of values that describe how to shape the data, or -1 if the size of the record is unknown.

As of version 6.0.0, rec_dims can be of type int or long.


String name of the data type of the record.

Return value

As described by the rec_dims and rec_type arguments.


fbindirread reads the rec_num record of the file path and shapes it according to the dimension sizes specified in the rec_dims parameter. The data type of the record is specified by the parameter rec_type. If the size and dimensionality of the record are unknown, the value -1 can be used for parameter rec_dims. In this case fbindirread will read in the entire file as a singly dimensioned array.

If written by Fortran, the file must have been been written to a file created by a Fortran "open" statement of the form

    open (..., access="direct", form="unformatted", recl=..., ...)

All records in the file must have the same dimensions and must be the same type.

Note: As with any binary file, the "endian-ness" of the data on the file and that of the current system must agree. The "ReadByteOrder" option in the setfileoption procedure can be used to force the "endian" type in a file. This allows big-endian files to be read on a little-endian machine and vice versa. The isbigendian function can be used to determine the endian-ness of your current system.

This function was updated in version 4.3.0 to allow reads into files bigger than 2 GB. This change allows you to access records that occur past the 2 GB point in the file.

This function was updated in version 6.0.0 to allow you to read variables larger than 2 GB if on a 64-bit system.

See Also

setfileoption, fbinnumrec, fbinrecread, fbinread, fbinrecwrite, fbinwrite isbigendian


  path = "/dummy/file.binary"
  nrec = 5
  dims = (/10,30/)
  x = fbindirread(path, nrec, dims, "float")
This will read the 6th record from "/dummy/file.binary" and return a two-dimensional [10 by 30] variable of type float to the variable "x".