Introduction
System variables are predefined variables which contain system-related information (e.g. system info[user name]) or configuration settings. e.g. runtime settings[verbose]. For most system variables, variable protections apply which may permit read-accesses, or impose restrictions on write accesses, e.g. limiting values to write to a selection of permitted values. See the list of system variables for existing system variables.
Demonstrating system and local variables
define procedure( foo, { { system info, numeral } } )
{
// Local variable system info[] is not accessible here because system
// variables are treated preferentially over local and global variables.
echo( "This is a ", scope( system info[]), " variable." );
echo( system info[operating system] );
}
foo( 123 );This is a system variable.
Windows