From 2cfde4152050063d8fa66b8c28f3b4b137d08a7a Mon Sep 17 00:00:00 2001

From: Shenghou Ma <[email protected]>

Date: Thu, 10 Sep 2015 02:32:12 -0400

Subject: [PATCH 33/63] [release-branch.go1.5] runtime/cgo: explicitly link

 msvcrt on windows

It's because runtime links to ntdll, and ntdll exports a couple

incompatible libc functions. We must link to msvcrt first and

then try ntdll.

Fixes #12030.

Change-Id: I0105417bada108da55f5ae4482c2423ac7a92957

Reviewed-on: https://go-review.googlesource.com/14472

Reviewed-by: Alex Brainman <[email protected]>

Run-TryBot: Minux Ma <[email protected]>

TryBot-Result: Gobot Gobot <[email protected]>

Reviewed-by: Ian Lance Taylor <[email protected]>

Reviewed-on: https://go-review.googlesource.com/16966

Run-TryBot: Austin Clements <[email protected]>

Reviewed-by: Minux Ma <[email protected]>

Reviewed-by: Russ Cox <[email protected]>

---

 misc/cgo/test/cgo_test.go   |  1 +

 misc/cgo/test/issue12030.go | 35 +++++++++++++++++++++++++++++++++++

 src/runtime/cgo/cgo.go      |  4 +++-

 3 files changed, 39 insertions(+), 1 deletion(-)

 create mode 100644 misc/cgo/test/issue12030.go

diff --git a/misc/cgo/test/cgo_test.go b/misc/cgo/test/cgo_test.go

index 9af31e8..4060338 100644

--- a/misc/cgo/test/cgo_test.go

+++ b/misc/cgo/test/cgo_test.go

@@ -65,5 +65,6 @@ func Test9026(t *testing.T)                  { test9026(t) }

 func Test9557(t *testing.T)                  { test9557(t) }

 func Test10303(t *testing.T)                 { test10303(t, 10) }

 func Test11925(t *testing.T)                 { test11925(t) }

+func Test12030(t *testing.T)                 { test12030(t) }

 func BenchmarkCgoCall(b *testing.B) { benchCgoCall(b) }

diff --git a/misc/cgo/test/issue12030.go b/misc/cgo/test/issue12030.go

new file mode 100644

index 0000000..ef8f86f

--- /dev/null

+++ b/misc/cgo/test/issue12030.go

@@ -0,0 +1,35 @@

+// Copyright 2015 The Go Authors.  All rights reserved.

+// Use of this source code is governed by a BSD-style

+// license that can be found in the LICENSE file.

+

+// Issue 12030. sprintf is defined in both ntdll and msvcrt,

+// Normally we want the one in the msvcrt.

+

+package cgotest

+

+/*

+#include <stdio.h>

+#include <stdlib.h>

+void issue12030conv(char *buf, double x) {

+	sprintf(buf, "d=%g", x);

+}

+*/

+import "C"

+

+import (

+	"fmt"

+	"testing"

+	"unsafe"

+)

+

+func test12030(t *testing.T) {

+	buf := (*C.char)(C.malloc(256))

+	defer C.free(unsafe.Pointer(buf))

+	for _, f := range []float64{1.0, 2.0, 3.14} {

+		C.issue12030conv(buf, C.double(f))

+		got := C.GoString(buf)

+		if want := fmt.Sprintf("d=%g", f); got != want {

+			t.Fatalf("C.sprintf failed for %g: %q != %q", f, got, want)

+		}

+	}

+}

diff --git a/src/runtime/cgo/cgo.go b/src/runtime/cgo/cgo.go

index cb24678..8f3e66f 100644

--- a/src/runtime/cgo/cgo.go

+++ b/src/runtime/cgo/cgo.go

@@ -20,7 +20,9 @@ package cgo

 #cgo !android,linux LDFLAGS: -lpthread

 #cgo netbsd LDFLAGS: -lpthread

 #cgo openbsd LDFLAGS: -lpthread

-#cgo windows LDFLAGS: -lm -mthreads

+// we must explicitly link msvcrt, because runtime needs ntdll, and ntdll

+// exports some incompatible libc functions. See golang.org/issue/12030.

+#cgo windows LDFLAGS: -lmsvcrt -lm -mthreads

 #cgo CFLAGS: -Wall -Werror

-- 

2.6.1