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go/misc/cgo/test/issue17537.go
Ian Lance Taylor 10f3b09027 cmd/cgo: don't strip qualifiers from C void* pointer
Now that we try to handle qualifiers correctly (as of CL 33325), don't
strip them from a void* pointer. Otherwise we break a case like "const
void**", as the "const" qualifier is dropped and the resulting
"void**" triggers a warning from the C compiler.

Fixes #18298.

Change-Id: If51df1889b0f6a907715298c152e6d4584747acb
Reviewed-on: https://go-review.googlesource.com/34370
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-12-14 00:59:38 +00:00

59 lines
1.2 KiB
Go

// Copyright 2016 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 17537. The void* cast introduced by cgo to avoid problems
// with const/volatile qualifiers breaks C preprocessor macros that
// emulate functions.
package cgotest
/*
#include <stdlib.h>
typedef struct {
int i;
} S17537;
int I17537(S17537 *p);
#define I17537(p) ((p)->i)
// Calling this function used to fail without the cast.
const int F17537(const char **p) {
return **p;
}
// Calling this function used to trigger an error from the C compiler
// (issue 18298).
void F18298(const void *const *p) {
}
// Test that conversions between typedefs work as they used to.
typedef const void *T18298_1;
struct S18298 { int i; };
typedef const struct S18298 *T18298_2;
void G18298(T18298_1 t) {
}
*/
import "C"
import "testing"
func test17537(t *testing.T) {
v := C.S17537{i: 17537}
if got, want := C.I17537(&v), C.int(17537); got != want {
t.Errorf("got %d, want %d", got, want)
}
p := (*C.char)(C.malloc(1))
*p = 17
if got, want := C.F17537(&p), C.int(17); got != want {
t.Errorf("got %d, want %d", got, want)
}
C.F18298(nil)
var v18298 C.T18298_2
C.G18298(C.T18298_1(v18298))
}