diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go
index 5ab78fdbf2..8264070569 100644
--- a/src/runtime/syscall_windows.go
+++ b/src/runtime/syscall_windows.go
@@ -42,20 +42,20 @@ func callbackasmAddr(i int) uintptr {
 //go:linkname compileCallback syscall.compileCallback
 func compileCallback(fn eface, cleanstack bool) (code uintptr) {
 	if fn._type == nil || (fn._type.kind&kindMask) != kindFunc {
-		panic("compileCallback: not a function")
+		panic("compileCallback: expected function with one uintptr-sized result")
 	}
 	ft := (*functype)(unsafe.Pointer(fn._type))
 	if len(ft.out()) != 1 {
-		panic("compileCallback: function must have one output parameter")
+		panic("compileCallback: expected function with one uintptr-sized result")
 	}
 	uintptrSize := unsafe.Sizeof(uintptr(0))
 	if ft.out()[0].size != uintptrSize {
-		panic("compileCallback: output parameter size is wrong")
+		panic("compileCallback: expected function with one uintptr-sized result")
 	}
 	argsize := uintptr(0)
 	for _, t := range ft.in() {
 		if t.size > uintptrSize {
-			panic("compileCallback: input parameter size is wrong")
+			panic("compileCallback: argument size is larger than uintptr")
 		}
 		argsize += uintptrSize
 	}
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 5cfdb76e2b..b234f3d67d 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -120,16 +120,16 @@ func (e Errno) Timeout() bool {
 // Implemented in runtime/syscall_windows.go.
 func compileCallback(fn interface{}, cleanstack bool) uintptr
 
-// Converts a Go function to a function pointer conforming
-// to the stdcall calling convention. This is useful when
-// interoperating with Windows code requiring callbacks.
+// NewCallback converts a Go function to a function pointer conforming to the stdcall calling convention.
+// This is useful when interoperating with Windows code requiring callbacks.
+// The argument is expected to be a function with with one uintptr-sized result. The function must not have arguments with size larger than the size of uintptr.
 func NewCallback(fn interface{}) uintptr {
 	return compileCallback(fn, true)
 }
 
-// Converts a Go function to a function pointer conforming
-// to the cdecl calling convention. This is useful when
-// interoperating with Windows code requiring callbacks.
+// NewCallbackCDecl converts a Go function to a function pointer conforming to the cdecl calling convention.
+// This is useful when interoperating with Windows code requiring callbacks.
+// The argument is expected to be a function with with one uintptr-sized result. The function must not have arguments with size larger than the size of uintptr.
 func NewCallbackCDecl(fn interface{}) uintptr {
 	return compileCallback(fn, false)
 }