Initial data commit

Task/Call-a-foreign-language-function/Go/call-a-foreign-language-function.go

@@ -0,0 +1,28 @@
+package main
+
+// #include <string.h>
+// #include <stdlib.h>
+import "C"
+import (
+    "fmt"
+    "unsafe"
+)
+
+func main() {
+    // a go string
+    go1 := "hello C"
+    // allocate in C and convert from Go representation to C representation
+    c1 := C.CString(go1)
+    // go string can now be garbage collected
+    go1 = ""
+    // strdup, per task. this calls the function in the C library.
+    c2 := C.strdup(c1)
+    // free the source C string.  again, this is free() in the C library.
+    C.free(unsafe.Pointer(c1))
+    // create a new Go string from the C copy
+    go2 := C.GoString(c2)
+    // free the C copy
+    C.free(unsafe.Pointer(c2))
+    // demonstrate we have string contents intact
+    fmt.Println(go2)
+}