## How to: Add an explicit usage file to a port.

`vcpkg` generates usage text for customers who install particular ports, if the customer names that
specific port. For example:

```
$> vcpkg install zlib:x64-windows
Computing installation plan...
The following packages will be built and installed:
  * vcpkg-cmake[core]:x64-windows -> 2022-09-26
    zlib[core]:x64-windows -> 1.2.12#2
Additional packages (*) will be modified to complete this operation.
Detecting compiler hash for triplet x64-windows...
Restored 2 package(s) from C:\Users\bion\AppData\Local\vcpkg\archives in 77.46 ms. Use --debug to see more details.
Installing 1/2 vcpkg-cmake:x64-windows...
Elapsed time to handle vcpkg-cmake:x64-windows: 10.32 ms
Installing 2/2 zlib:x64-windows...
Elapsed time to handle zlib:x64-windows: 20.89 ms
Total elapsed time: 2.747 s

The package zlib is compatible with built-in CMake targets:

    find_package(ZLIB REQUIRED)
    target_link_libraries(main PRIVATE ZLIB::ZLIB)
```

If there is no explicit usage installed by the port, vcpkg will generate default usage text by
inspecting with the port installs. If the default usage text is suboptimal, it can be overridden by
a port installing a file named "usage" in its "share" directory.

1. Create a file named `usage` in the port directory, with the content you want displayed.
2. To `portfile.cmake`, add
```
file(INSTALL "${CMAKE_CURRENT_LIST_DIR}/usage" DESTINATION "${CURRENT_PACKAGES_DIR}/share/${PORT}")
```
3. Update the port-version and rerun `vcpkg x-add-version` if necessary.