#if Waldo Bastian > You will have to run 10 or so instances of each to see the actual effects on > your free memory, since these numbers are a bit crappy (e.g. you don't know > how much is actually shared between processes). Ok, 10 instances of each. Using the 'application' example this time. Information from 'free', using the '-/+ buffers/cache -> used' section: === No exceptions Before: 129876 After: 143812 Growth: 13936 === Using exceptions Before: 129684 After: 152744 Growth: 23060 So with -no-g++-exceptions, 13.6M is needed. Without the flag, 22.5M. That's 0.89M per process. > VmRSS shows that the memory actually used (non-virtual memory) increases with > 2100Kb, unfortunately it is not clear how much of the 1460Kb shared vm is > responsible for this and how much of 1316Kb non-shared vm is responsible for > this. It would not surprise me if all of the 1316Kb would end up here. That > would mean that the overhead of exceptions is 1.3Mb / process due to Qt > alone. (kdelibs will probably double this then) It looks like it's not the full 1.3M / process, but 0.89M is still very significant. If I had compiled KDE with exception support, this would be even worse. As I said earlier, I don't think it's likely that we'll ever use C++ exceptions, but at least this information is useful in that it shows that -fno-exceptions is a very good idea ! I have 25 processes running which link to libqt. > 22.25M wasted memory ? No thanks :) Rik