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16.2 C-Style I/O Functions

Octave's C-style input and output functions provide most of the functionality of the C programming language's standard I/O library. The argument lists for some of the input functions are slightly different, however, because Octave has no way of passing arguments by reference.

In the following, file refers to a file name and fid refers to an integer file number, as returned by fopen.

There are three files that are always available. Although these files can be accessed using their corresponding numeric file ids, you should always use the symbolic names given in the table below, since it will make your programs easier to understand.

— Built-in Constant: stdin

The standard input stream (file id 0). When Octave is used interactively, this is filtered through the command line editing functions.
See also: stdout, stderr.

— Built-in Constant: stdout

The standard output stream (file id 1). Data written to the standard output is normally filtered through the pager.
See also: stdin, stderr.

— Built-in Constant: stderr

The standard error stream (file id 2). Even if paging is turned on, the standard error is not sent to the pager. It is useful for error messages and prompts.
See also: stdin, stdout.