ltrace

USE flags

• debug - Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
• elfutils - Use libdwfl from sys-libs/libunwind for frame unwinding support
• selinux - !!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
• test - Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
• unwind - Use sys-libs/libunwind for frame unwinding support