You may be able to make use of select, or if that doesn't work for you then you may have to issue a special sysopen call with certain bits set in the mode parameter but alas I cannot remember what they are at the moment.

UPDATE: I found this node which explains what the mode should be for the sysopen.

metadoktor

"The doktor is in."

In reply to Use select function or adjust flag bits of mode parameter to sysopen - Re: non-blocking reading by metadoktor
in thread non-blocking reading by Anonymous Monk

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