There are three different variables to register a conflict between packages and ports: CONFLICTS, CONFLICTS_INSTALL and CONFLICTS_BUILD.
Note: The conflict variables automatically set the variable IGNORE, which is more fully documented in Section 12.14.
When removing one of several conflicting ports, it is advisable to retain the CONFLICTS entries in those other ports for a few months to cater for users who only update once in a while.
If your package cannot coexist with other packages (because of file conflicts, runtime incompatibilities, etc.), list the other package names in the CONFLICTS_INSTALL variable. You can use shell globs like * and ? here. Package names should be enumerated the same way they appear in /var/db/pkg. Please make sure that CONFLICTS_INSTALL does not match this port's package itself. Otherwise enforcing its installation with FORCE_PKG_REGISTER will no longer work. The CONFLICTS_INSTALL check is done after the build stage and prior to the install stage.
If your port cannot be built if a certain port is already installed, list the other port names in the CONFLICTS_BUILD variable. You can use shell globs like * and ? here. Package names should be enumerated the same way they appear in /var/db/pkg. The CONFLICTS_BUILD check is done prior to the build stage. Build conflicts are not recorded in the resulting package.
If your port cannot be built if a certain port is already installed and the resulting package cannot coexist with the other package, list the other package name in the CONFLICTS variable. You can use shell globs like * and ? here. Packages names should be enumerated the same way they appear in /var/db/pkg. Please make sure that CONFLICTS_INSTALL does not match this port's package itself. Otherwise enforcing its installation with FORCE_PKG_REGISTER will no longer work. The CONFLICTS check is done prior to the build stage and prior to the install stage.