23. Adding a Find Module for Third-Party Libraries¶

VisIt uses custom Find modules for most of its dependent third-party libraries. The Find modules live in src/CMake and most of them utilize special functions that live in src/CMake/SetUpThirdParty.cmake. The most important of these is SET_UP_THIRD_PARTY, as it does the bulk of the work in determining platform-specific extensions, handles .so versioning and Windows dll’s and import libraries.

The first argument to the function is the name of the package (eg FOO), and it expects a capitalized package name that corresponds to a VISIT_<PKG>_DIR entry in VisIt’s config-site files. This function also uses these keyword arguments:

LIBS: required: The name(s) of the library(ies) without platform-specific prefixes, suffixes or extensions. For example: SETUP_THIRD_PARTY(FOO LIBS foo1 foo2), not SETUP_THIRD_PARTY(FOO LIBS libfoo1.so libfoo2.so).
LIBDIR: optional: The paths beyond VISIT_<PKG>_DIR where the libraries may be found. VISIT_<PKG>_DIR/lib or VISIT_<PKG>_DIR>/lib64 will be assumed if this is not provided.
INCDIR: optional: The path beyond VISIT_<PKG>_DIR where the headers may be found. VISIT_<PKG>_DIR/include will be assumed if this is not provided.

There may be situations where this simple solution is not sufficient: a package may have already created its own Find module and duplication of effort isn’t desired; or the package may be complex with many components all of which may not necessarily be needed by VisIt (e.g. VTK). For situations where this function is not sufficient, standard CMake find calls (find_path, find_library, find_package) may be used along with the necessary special INSTALL commands for ensuring the package’s libraries (and possibly headers) are installed alongside VisIt.

The INSTALL commands that VisIt uses are custom functions:

THIRD_PARTY_INSTALL_LIBRARY(LIBFILE):

Installs the library file.

LIBFILE is the full path to a library file.

THIRD_PARTY_INSTALL_INCLUDE(pkg incdir)

Installs pkg’s headers.

pkg is the name of the package.

incdir1 is the full path to the headers (root of include tree if it involves multiple subdirectories).