Build options¶

Pass options during configuration with -DNAME=VALUE:

Option	Default	Effect
`ENABLE_PYTHON`	`ON`	build and install `pyhermes`
`ENABLE_TESTING`	`OFF`	build the C++ test suite and enable CTest
`DOWNLOAD_DATA`	`OFF`	download and SHA-256 verify the pinned runtime archive
`HERMES_INSTALL_DATA`	`ON`	install data available in `HERMES_DATA_SOURCE_DIR`
`ENABLE_SYS_HDF5`	`OFF`	opt into unmaintained PICARD/HDF5 support
`HERMES_ENABLE_FAST_MATH`	`OFF`	permit non-IEEE compiler math optimizations
`HERMES_UNIT_SYSTEM_OPTION`	`ON`	retain compile-time physical-dimensional checks
`ENABLE_GIT`	`ON`	embed Git version information when available
`USE_ABSOLUTE_RPATH`	`OFF`	embed the configured absolute install library path

Important cache paths:

Variable	Meaning
`CMAKE_INSTALL_PREFIX`	root of the C++/Python/data installation
`Python3_EXECUTABLE`	interpreter whose ABI is used by `pyhermes`
`HERMES_PYTHON_INSTALL_DIR`	prefix-relative Python extension destination
`HERMES_DATA_SOURCE_DIR`	unpacked data used by the build/install
`HERMES_DATA_ARCHIVE`	local archive path
`HERMES_DATA_URL`	versioned archive URL
`HERMES_DATA_SHA256`	expected archive digest
`HERMES_INSTALL_CMAKEDIR`	installed `HermesConfig.cmake` destination

Inspect the effective configuration:

cmake -S . -B build -LAH

When changing Python, install prefix, data version, compiler, or major optional features, use a fresh build directory. A cached CMake result can otherwise keep an earlier interpreter or archive URL.