What does the error "CPU you selected does not support x86-64 instruction set" mean?

Question

I installed Point Cloud Library from the ppa for in Ubuntu 11.10 x86_64 (including the dev packages, not necessarily relevant for the question but for the sake of completeness I am providing this detail). When I am trying to compile (make on a cmake generated make file) my own code which uses pcl I am getting the error CPU you selected does not support x86-64 instruction set. What does this error mean and what all should I check in order to remove the error?

Answer 1

This means that you're passing a flag to gcc which selects a CPU type that doesn't support 64bit. For example, maybe you're using a flag like -march=prescott or similar. What does your compile line look like? Some useful information about flags can be found on the Gentoo (where else?) wiki: http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel

Answer 2

Are you running on a 64 bit machine?

looks like the software is for 64 bit machines and you have a 32 bit processor.