diff --git a/windows/syscall_test.go b/windows/syscall_test.go index 62588b91..d7009e44 100644 --- a/windows/syscall_test.go +++ b/windows/syscall_test.go @@ -7,6 +7,7 @@ package windows_test import ( + "syscall" "testing" "golang.org/x/sys/windows" @@ -31,3 +32,22 @@ func TestEnv(t *testing.T) { // make sure TESTENV gets set to "", not deleted testSetGetenv(t, "TESTENV", "") } + +func TestGetProcAddressByOrdinal(t *testing.T) { + // Attempt calling shlwapi.dll:IsOS, resolving it by ordinal, as + // suggested in + // https://msdn.microsoft.com/en-us/library/windows/desktop/bb773795.aspx + h, err := windows.LoadLibrary("shlwapi.dll") + if err != nil { + t.Fatalf("Failed to load shlwapi.dll: %s", err) + } + procIsOS, err := windows.GetProcAddressByOrdinal(h, 437) + if err != nil { + t.Fatalf("Could not find shlwapi.dll:IsOS by ordinal: %s", err) + } + const OS_NT = 1 + r, _, _ := syscall.Syscall(procIsOS, 1, OS_NT, 0, 0) + if r == 0 { + t.Error("shlwapi.dll:IsOS(OS_NT) returned 0, expected non-zero value") + } +} diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go index 9b5ed549..acd06e36 100644 --- a/windows/syscall_windows.go +++ b/windows/syscall_windows.go @@ -202,6 +202,21 @@ func NewCallbackCDecl(fn interface{}) uintptr { // syscall interface implementation for other packages +// GetProcAddressByOrdinal retrieves the address of the exported +// function from module by ordinal. +func GetProcAddressByOrdinal(module Handle, ordinal uintptr) (proc uintptr, err error) { + r0, _, e1 := syscall.Syscall(procGetProcAddress.Addr(), 2, uintptr(module), ordinal, 0) + proc = uintptr(r0) + if proc == 0 { + if e1 != 0 { + err = errnoErr(e1) + } else { + err = syscall.EINVAL + } + } + return +} + func Exit(code int) { ExitProcess(uint32(code)) } func makeInheritSa() *SecurityAttributes {