setupapi: safer aliasing of slice types

2 files changed, 13 insertions, 10 deletions

diff --git a/tun/wintun/guid/guid_windows.go b/tun/wintun/guid/guid_windows.go
index 0078d2c..c5f4be6 100644
--- a/tun/wintun/guid/guid_windows.go
+++ b/tun/wintun/guid/guid_windows.go
@@ -12,7 +12,7 @@ import (
 	"golang.org/x/sys/windows"
 )
 
-//sys	clsidFromString(lpsz *uint16, pclsid *windows.GUID) (hr int32) = ole32.CLSIDFromString
+//sys	clsidFromString(lpsz *uint16, pclsid *windows.GUID) (err error) [failretval!=0] = ole32.CLSIDFromString
 
 //
 // FromString parses "{XXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX}" string to GUID.
@@ -22,14 +22,11 @@ func FromString(str string) (*windows.GUID, error) {
 	if err != nil {
 		return nil, err
 	}
-
 	guid := &windows.GUID{}
-
-	hr := clsidFromString(strUTF16, guid)
-	if hr < 0 {
-		return nil, syscall.Errno(hr)
+	err = clsidFromString(strUTF16, guid)
+	if err != nil {
+		return nil, err
 	}
-
 	return guid, nil
 }
 
diff --git a/tun/wintun/guid/zguid_windows.go b/tun/wintun/guid/zguid_windows.go
index 5467849..b0b4cce 100644
--- a/tun/wintun/guid/zguid_windows.go
+++ b/tun/wintun/guid/zguid_windows.go
@@ -42,8 +42,14 @@ var (
 	procCLSIDFromString = modole32.NewProc("CLSIDFromString")
 )
 
-func clsidFromString(lpsz *uint16, pclsid *windows.GUID) (hr int32) {
-	r0, _, _ := syscall.Syscall(procCLSIDFromString.Addr(), 2, uintptr(unsafe.Pointer(lpsz)), uintptr(unsafe.Pointer(pclsid)), 0)
-	hr = int32(r0)
+func clsidFromString(lpsz *uint16, pclsid *windows.GUID) (err error) {
+	r1, _, e1 := syscall.Syscall(procCLSIDFromString.Addr(), 2, uintptr(unsafe.Pointer(lpsz)), uintptr(unsafe.Pointer(pclsid)), 0)
+	if r1 != 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
 	return
 }