How to change PQexec timeout?

Dear postgreSQL experts,
could you explain me how can I dynamically change  time-out value for
each PQexec() call? Or at least how can I set time-out for my current
program?
I found
void setQueryTimeout (int seconds)
in libodbc++ documentation, but nothing of this kind in libpq. Should I
install libodbc++ to manipulate time-out value, or there is something in
postgreSQL itself?
Thank you, Sergey.

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Sergey V Belikov            home phone:   (631)924-0458
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