From 5ba01674fb5ea57a03d0957c6320b7ed935845db Mon Sep 17 00:00:00 2001
From: xushiwei <x@goplus.org>
Date: Sun, 14 Jul 2024 10:56:19 +0800
Subject: [PATCH] README: How support C and Python

---
 README.md                  | 39 ++++++++++++++++++++++++++++++++++++++
 _demo/linkname/linkname.go | 10 ++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 _demo/linkname/linkname.go

diff --git a/README.md b/README.md
index 995a11ef..c6c1a4f2 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,45 @@ LLGo := Go + C + Python
 LLGo is compatible with C and Python through the language's **Application Binary Interface (ABI)**, while LLGo is compatible with Go through its **syntax (source code)**.
 
 
+## How support C and Python
+
+LLGo use `go:linkname` to link an extern symbol througth its **Application Binary Interface (ABI)**:
+
+```go
+import _ "unsafe" // for go:linkname
+
+//go:linkname Sqrt C.sqrt
+func Sqrt(x float64) float64
+```
+
+You can directly integrate it into [your own code](_demo/linkname/linkname.go):
+
+```go
+package main
+
+import _ "unsafe" // for go:linkname
+
+//go:linkname Sqrt C.sqrt
+func Sqrt(x float64) float64
+
+func main() {
+	println("sqrt(2) =", Sqrt(2))
+}
+```
+
+Or put it into a package (see [c/math](c/math/math.go)):
+
+```go
+package main
+
+import "github.com/goplus/llgo/c/math"
+
+func main() {
+	println("sqrt(2) =", math.Sqrt(2))
+}
+```
+
+
 ## C/C++ standard libary support
 
 You can import a C/C++ standard library in LLGo!
diff --git a/_demo/linkname/linkname.go b/_demo/linkname/linkname.go
new file mode 100644
index 00000000..b9c1686e
--- /dev/null
+++ b/_demo/linkname/linkname.go
@@ -0,0 +1,10 @@
+package main
+
+import _ "unsafe" // for go:linkname
+
+//go:linkname Sqrt C.sqrt
+func Sqrt(x float64) float64
+
+func main() {
+	println("sqrt(2) =", Sqrt(2))
+}