Datasheet

Standard C Implementation Definition
B-4 Copyright © 1999-2001 ARM Limited. All rights reserved. ARM DUI 0067D
Interactive device
In an unhosted implementation of the ARM C library, the term interactive device might
be meaningless. The generic ARM C library supports a pair of devices, both called
:tt ,
intended to handle keyboard input and VDU screen output. In the generic
implementation:
• no buffering is done on any stream connected to
:tt unless input/output
redirection has occurred
• if input/output redirection other than to
:tt has occurred, full file buffering is used
(except that line buffering is used if both
stdout and stderr were redirected to the
same file).
Standard input, output, and error streams
Using the generic ARM C library, the standard input (
stdin ), output ( stdout ) and error
streams (
stderr ) can be redirected at runtime. For example, if mycopy is a program,
running on a host debugger, that copies the standard input to the standard output, the
following line runs the program:
mycopy < infile > outfile 2> errfile
and redirects the files as follows:
stdin The file is redirected to infile
stdout
The file is redirected to outfile
stderr
The file is redirected to errfile .
The permitted redirections are:
0< filename This reads stdin from filename .
< filename This reads stdin from filename .
1> filename This writes stdout to filename .
> filename This writes stdout to filename .
2> filename This writes stderr to filename .
2>&1 This writes stderr to the same place as stdout .
>& file This writes both stdout and stderr to filename .
>> filename This appends stdout to filename .