Today i try install OpenCv in my MacOs Snow Leopard 10.6 and have this error:

error: CPU you selected does not support x86-64 instruction set

The searching in google have the solution

go to opencv folder and edit configure file, searchi prescott and replace the line

DEFAULT_CXXFLAGS="-g -march=prescott -ffast-math -fomit-frame-pointer $DEFAULT_CXXFLAGS"

with this:

DEFAULT_CXXFLAGS="-g -march=i686 -m32 -ffast-math -fomit-frame-pointer $DEFAULT_CXXFLAGS"

But when i try to compile i have other error i now looking for how to resolve it

Now i can install opencv lib with macport!!!

1.- i have old macport then first i need clean and delete it.

port installed > myports.txt

sudo port clean installed

sudo port -f uninstall installed

2.- Install ports you need you can see myports.txt to know the old ports you have installed before clean.

3.- Patch the opencv port: see and download the patch Portfile-sl_64bit_21014.diff

4.- Follow the instruction in post of patch

Check where you installed macports, that is usually /opt/local/ Locate the Portfile for OpenCV, for me that is at


now apply the third patch (Portfile-sl_64bit_21014.diff) by executing

sudo patch Portfile -i ~/Downloads/Portfile-sl_64bit_21014.diff

in the above directory (adjust the last path accordingly to your download location)

When you execute port variants opencv you should see the sl_64bit_21014 variant. Now install opencv with

sudo port install opencv +sl_64bit_21014