6.3 The STANDARD-IO module
*standard-error*
Variable
Summary
The standard error stream.
Library
io
Module
standard-io
Type
<stream>
Initial value
The standard error stream for the platform on which the application is running.
Description
This variable is bound to an output stream that sends error messages to the standard error location for the platform on which the application is running. It is equivalent to the Java stream java.lang.System.err.
If the platform has a notion of standard streams, such as MS-DOS, this stream maps onto the platform-specific standard error stream. If the platform has no such convention, such as a platform that is primarily window-based, a console window is created for this stream if necessary, just to capture output to it.
If a console window has already been created as a result of writing to or reading from one of the other variables in the Standard-IO module, then the existing console window is used, and a new one is not created: a single console window is used for all variables in this module.