Question about ' !insertmacro InstallLib '

If a library has already been installed on the target computer, I don't want the installer to install it again.
Is there any possible way of controlling this?
I checked all the parameters/options for this marco, but none of them is for this.
Anybody can help? Thanks.

Will an IfFileExists check not do?

Stu

problem is we don't where the library is on the target machine. I know it's possible to check the file location of
a registered library in the registry. But i don't think that's safe. Is there any other way of doing this?

Locate perhaps?