build: Support tools and examples with multiple translation units
Change-Id: I71a5690391464d8275b91f55e914c004eed4f360
Refs: #2344
diff --git a/examples/README.md b/examples/README.md
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+ndn-cxx examples
+================
+
+By default, examples in `examples/` folder are not built. To enable them, use
+`--with-examples` configure option. For example:
+
+ ./waf configure --with-examples
+ ./waf
+
+There are two ways to add new examples, depending on their complexity:
+
+1. Examples with a single translation unit
+
+ For simple examples that have a single translation unit, the `.cpp` file can be directly put
+ in `examples/` folder and it will be automatically compiled on the next run of `./waf`. Name
+ of the compiled binary will be determined by the base name of the `.cpp` file. For example,
+ `examples/foo.cpp` will be compiled into binary `foo` in `<build>/examples` folder:
+
+ echo "int main() { return 0; }" > examples/foo.cpp
+ ./waf
+ # ... Compiling examples/foo.cpp
+ # ... Linking build/examples/foo
+
+ # To run the example
+ ./build/examples/foo
+
+2. Examples with multiple translation units
+
+ For more complex examples that contain multiple translation units, one can use
+ the following directory structure:
+
+ - Create a directory under `examples/` folder (e.g., `examples/bar`).
+ The name of this directory will determine the name of the compiled binary
+ (`<build>/examples/bar/bar`)
+
+ - Place any number of translation units (e.g., `examples/bar/a.cpp`, `examples/bar/b.cpp`,
+ ...) in this directory. All `.cpp` files in this directory will be compiled and linked
+ together to produce the binary of the example. One of the .cpp files should contain
+ the `main()` function.
+
+ For example:
+
+ mkdir examples/bar
+ echo "int bar(); int main() { return bar(); }" > examples/bar/a.cpp
+ echo "int bar() { return 10; } " > examples/bar/b.cpp
+ ./waf
+ # ... Compiling examples/bar/a.cpp
+ # ... Compiling examples/bar/b.cpp
+ # ... Linking build/examples/bar/bar
+
+ # To run the example
+ ./build/examples/bar/bar