IVar
IVars are write-once (immutable) variables.
They can be read, an operation that will block until a value was written to the variable. They can be written to exactly once.
Version 0.3
Environment variables.
Write-once variables, with the ability to block on the first of a set of variables to become available.
Version 0.30
Gets the values of all CGI variables from the program environment.
variable