FLUSH TABLES hangs if table is locked

Using FLUSH TABLES via the C query API mysql_query() hangs if the table is
locked already. That is to say, nothing prevents me from running a LOCK
TABLES twice; it won't tell me "it's already locked, don't try to run a
FLUSH".

Anyone know how to find out if a table is already locked? And don't say
"call the DBA"

TIA

The Bunny