c++filt: note to demangle type

1 files changed, 35 insertions, 1 deletions

diff --git a/src/development/c++filt.md b/src/development/c++filt.md
index 2592ba9..38607ee 100644
--- a/src/development/c++filt.md
+++ b/src/development/c++filt.md
@@ -2,7 +2,8 @@
 
 ## Demangle symbol
 ```markdown
-  c++-filt <symbol_str>
+  c++-filt [opts] <symbol_str>
+    -t    Try to also demangle types.
 ```
 
 ## Demangle stream
@@ -10,3 +11,36 @@ For example dynamic symbol table:
 ```markdown
   readelf -W --dyn-syms <elf> | c++filt
 ```
+
+## Demangle types
+```c++
+// file: type.cc
+#include <cstdio>
+#include <typeinfo>
+
+#define P(ty) printf(#ty " -> %s\n", typeid(ty).name())
+
+template <typename T = void>
+struct Foo {};
+
+int main() {
+  P(int);
+  P(unsigned char);
+  P(Foo<>);
+  P(Foo<int>);
+}
+```
+Build and run:
+```sh
+$ clang++ type.cc && ./a.out | c++filt
+int -> i
+unsigned char -> h
+Foo<> -> 3FooIvE
+Foo<int> -> 3FooIiE
+
+$ clang++ type.cc && ./a.out | c++filt -t
+int -> int
+unsigned char -> unsigned char
+Foo<> -> Foo<void>
+Foo<int> -> Foo<int>
+```