# CMake Installation

**`install(TARGETS target DESTINATION bin)` installs a target to the specified directory under `CMAKE_INSTALL_PREFIX`**. The default prefix is `/usr/local` on Unix. Run `cmake --install .` to install after building.

Installing executables:

```cmake
add_executable(myapp main.cpp)
install(TARGETS myapp DESTINATION bin)
```

This installs the executable to `<prefix>/bin/myapp`.

Installing libraries:

```cmake
add_library(mylib source.cpp)
install(TARGETS mylib
  LIBRARY DESTINATION lib
  ARCHIVE DESTINATION lib
  RUNTIME DESTINATION bin)
```

- `LIBRARY` — shared libraries (.so, .dylib)
- `ARCHIVE` — static libraries (.a, .lib)
- `RUNTIME` — DLLs on Windows

Installing headers:

```cmake
install(FILES include/mylib.h DESTINATION include)
install(DIRECTORY include/ DESTINATION include)
```

The first installs a single file; the second installs a directory recursively.

Setting the install prefix:

```bash
cmake -DCMAKE_INSTALL_PREFIX=/usr ..
cmake --install .
```

Or in CMakeLists.txt:

```cmake
set(CMAKE_INSTALL_PREFIX /usr/local)
```

Common directory structure:

```cmake
install(TARGETS myapp DESTINATION bin)
install(TARGETS mylib DESTINATION lib)
install(FILES include/mylib.h DESTINATION include)
install(FILES README.md DESTINATION share/doc/mylib)
```

Exporting targets for consumers:

```cmake
install(TARGETS mylib EXPORT mylib-targets
  LIBRARY DESTINATION lib
  ARCHIVE DESTINATION lib)

install(EXPORT mylib-targets DESTINATION lib/cmake/mylib)
```

This generates CMake config files so other projects can `find_package(mylib)` and link to your installed library.

Installation rules are evaluated at install time, not configuration time. Use conditionals sparingly (they're evaluated at config time). Use `cmake --install . --verbose` to see what's being installed.

Packaging:

```cmake
set(CPACK_PACKAGE_NAME "myapp")
set(CPACK_PACKAGE_VERSION "1.0.0")
include(CPack)
```

This enables `cpack` to generate platform-specific installers (.tar.gz, .deb, .rpm, .msi).

Install rules are typically at the end of your main CMakeLists.txt. Always use absolute paths or `CMAKE_INSTALL_PREFIX` variables.