Para openSUSE Tumbleweed execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:psych0naut/openSUSE_Tumbleweed/home:psych0naut.repo
zypper refresh
zypper install gpp
Para openSUSE Factory execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:psych0naut/openSUSE_Factory/home:psych0naut.repo
zypper refresh
zypper install gpp
Para 15.5 execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:psych0naut/15.5/home:psych0naut.repo
zypper refresh
zypper install gpp
Para 15.4 execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/home:psych0naut/15.4/home:psych0naut.repo
zypper refresh
zypper install gpp