Global USE flags

Flag Description Packages
debug 3
doc Install related README.md 6
examples Install examples (you compile them rn in any case) 5
nls 2
static-libs Make static library. If you are on windows, enable only one of `static-libs` and `shared-libs` 3
test 13
tools Build and install extra command line tools 2

Category USE flags

dev-cpp

Flag Description Packages
benchmarks Build benchmarks 2

llvm-runtimes

Flag Description Packages
abi_x86_32 2
abi_x86_64 2
clang 2

Local USE flags

dev-cpp

boost-ut

Flag Description
experimental-c++-modules EXPERIMANTAL Try to enable C++ modules target.
test-valgrind Run tests with valgrind

glaze

Flag Description
eetf-format Support for ettf
fuzzing Build fuzzers (not install)

kokkos

Flag Description
cuda Enable the CUDA execution space. Any Kokkos application compiled for CUDA embeds CUDA code via template metaprogramming. Thus, the whole application must be built with a CUDA-capable compiler. (At the moment, the only such compilers are NVIDIA’s NVCC and Clang 10.0+)
hip Enable the HIP execution space. Requires a compiler capable of understanding HIP.
openmp Enable the OpenMP execution space. Requires the compiler to support OpenMP (e.g., -fopenmp).
serial Enable the Serial execution space.(Single thread without parallelization support)
sycl Enable the SYCL execution space. Requires a compiler capable of understanding SYCL.
threads Enable the C++ Threads execution space. (aka multithread support)

quill

Flag Description
extensive-test Build extensive_tests
valgrind Test with valgrind

dev-libs

boost

Flag Description
${PYTHON_REQUIRED_USE}
boost-context-fcontext Boost.Context implementation. Default on not-windows OS. https://www.boost.org/doc/libs/1_87_0/libs/context/doc/html/context/cc/implementations__fcontext_t__ucontext_t_and_winfiber.html
boost-context-ucontext Boost.Context implementation. Deprecated. https://www.boost.org/doc/libs/1_87_0/libs/context/doc/html/context/cc/implementations__fcontext_t__ucontext_t_and_winfiber.html
boost-context-winfib Boost.Context implementation. Windows only. https://www.boost.org/doc/libs/1_87_0/libs/context/doc/html/context/cc/implementations__fcontext_t__ucontext_t_and_winfiber.html
boost-iostream-bzip2 When ON, enables BZip2 support. Defaults to ON when libbzip2 is found, OFF otherwise.
boost-iostream-lzma When ON, enables LZMA support. Defaults to ON when liblzma is found, OFF otherwise.
boost-iostream-zlib When ON, enables ZLib support. Defaults to ON when zlib is found, OFF otherwise.
boost-iostream-zstd When ON, enables Zstd support. Defaults to ON when libzstd is found, OFF otherwise.
boost-locale-iconv When ON, enables the Iconv backend. Defaults to ON when iconv is found, OFF otherwise. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
boost-locale-icu When ON, enables the ICU backend. Defaults to ON when ICU is found, OFF otherwise. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
boost-locale-posix When ON, enables the POSIX backend. Defaults to ON on POSIX systems, OFF otherwise. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
boost-locale-std When ON, enables the std::locale backend. Defaults to ON. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
boost-locale-winapi When ON, enables the Windows API backend. Defaults to ON under Windows, OFF otherwise. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
boost-stacktrace-addr2line Boost.Stacktrace: build boost_stacktrace_addr2line
boost-stacktrace-backtrace Boost.Stacktrace: build boost_stacktrace_backtrace
boost-stacktrace-basic Boost.Stacktrace: build boost_stacktrace_basic
boost-stacktrace-from-exception Boost.Stacktrace: build boost_stacktrace_from_exception
boost-stacktrace-noop Boost.Stacktrace: build boost_stacktrace_noop
boost-stacktrace-windbg Boost.Stacktrace: build boost_stacktrace_windbg
boost-stacktrace-windbg-cached Boost.Stacktrace: build boost_stacktrace_windbg_cached
boost-thread-pthread Threading API, pthread or win32. Defaults to win32 under Windows, pthread otherwise.
boost-thread-win32 Threading API, pthread or win32. Defaults to win32 under Windows, pthread otherwise.
bzip2 yet another USE flag for compability with gentoo's ebuild. Requires boost-iostream-bzip2
context yet another USE flag for compability with gentoo's ebuild. Requires any boost-context-* flag.
icu
lzma yet another USE flag for compability with gentoo's ebuild. Requires boost-iostream-lzma
mpi Set to ON if Boost libraries depending on MPI should be built. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
numpy lol, yet another USE flag for compability with gentoo's ebuild. Always enabled. If you try disable it, get destroyed.
python Set to ON if Boost libraries depending on Python should be built. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
stacktrace yet another USE flag for compability with gentoo's ebuild. WARNING: you can enable multiple boost-stacktrace-* USE flags, but the logic of what will be the Boost::stacktrace cmake's target is a default priority on top of if the stacktrace backend is possible: windbg -> backtrace -> addr2line -> basic -> noop. At least that how it is now (march 2025)
static Set to ON if Boost libraries should be build as static libraries. https://github.com/boostorg/cmake/tree/7f5336b3bf8067bb40da4e8b9940c133271e938a?tab=readme-ov-file
zlib yet another USE flag for compability with gentoo's ebuild. Requires boost-iostream-zlib
zstd yet another USE flag for compability with gentoo's ebuild. Requires boost-iostream-zstd

simdjson

Flag Description
all-impls Enable all (possibly supported by CHOST) implementations rather than only of them.
shared-libs Make shared library. If you are on windows, enable only one of `static-libs` and `shared-libs`
singleheader Make simdjson library out of amalgamated one simdjson.hpp and one simdjson.cpp, instead of whole bunch of files in include/ and src/ . Expected to be more stable.

llvm-runtimes

compiler-rt-bloomberg-p2996

Flag Description
atomic-builtins

compiler-rt-sanitizers-bloomberg-p2996

Flag Description
${SANITIZER_FLAGS[*]}
(
)
asan
cfi
ctx-profile
dfsan
gwp-asan
hwasan
libfuzzer
lsan
memprof
msan
nsan
orc
profile
rtsan
safestack
scudo
shadowcallstack
tsan
ubsan
xray

sys-devel

clang-bloomberg-p2996

Flag Description
default-reflection-latest
llvm_targets_
pie

www-client

w3m

Flag Description
X
fbcon
gdk-pixbuf Enable support for <pkg>x11-libs/gdk-pixbuf</pkg>
gpm
imlib
l10n_ja
lynxkeymap If you prefer Lynx-like key binding
nntp
ssl
unicode
xface