4.3.6 The NOTREADY condition The condition NOTREADY is a condition of mixed origin. It is raised as a result of problems with stream I/O. Exactly what causes it, may vary between implementations, but some of the more probable causes are: waiting for more I/O on transient streams; access to streams not allowed; I/O operation would block if attempted; etc. See the chapter; Stream Input and Output for more information. Differences between NOTREADY and the standard condition are: · It will be ignored rather than queued if condition trap is in state DELAY. · This condition differs from the rest in that it can be raised during execution of a clause, but can still be trapped by method CALL. The descriptive text returned by CONDITION() when called with the Description option for condition NOTREADY, is the name of the stream which caused the problem. This is probably the same string that you used as the first parameter to the functions that operates on stream I/O. For the default streams (default input and output stream), the string returned by CONDITION() will be nullstrings. Note that if the NOTREADY trap is in state DELAY, then all I/O for files which has tried to raise NOTREADY within the current clause will be simulated as if operation had succeeded.
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