datetime(): Where is it in the docs? - Mailing list pgsql-general

I find myself using the datetime() function a lot (as in
to_char(datetime(x), 'MM-DD')) but to be honest I don't really know what
it does.

I've looked in the online interactive docs but can't find a description
of it anywhere, just an example.

Can someone point me to a definition of the function?

Thanks!

Jc