protected Semaphore is
entry Seize;
entry Release;
private
Busy : Boolean := False;
end Semaphore;
protected body Semaphore is
entry Seize when not Busy is
begin
Busy := True;
end;
entry Release when Busy is
begin
Busy := False;
end;
end Semaphore;
function Gethostbyname (Name : in System.Address)
return System.Address; -- pointer to hostent
pragma Import(C, Gethostbyname);
function Protected_Gethostbyname (Name : in System.Address)
return System.Address is
Result : System.Address;
begin
Semaphore.Seize;
Result := Gethostbyname(Name);
Semaphore.Release;
return Result;
exception
when others =>
Semaphore.Release;
raise;
end Protected_Gethostbyname;
it would be nice to put the call to gethostbyname inside a protected
procedure (so that you need only one protected call instead of two), but
this does not seem to be allowed as gethostbyname could be potentially blocking.
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