In C, a function argument written as a fixed size array
actually requires a pointer to the first element of the array.
C compilers are aware of this calling convention and adjust
the call accordingly, but Go cannot. In Go, you must pass
the pointer to the first element explicitly: C.f(&C.x[0]).

Calling variadic C functions is not supported. It is possible to
circumvent this by using a C function wrapper. For example:

	package main

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build gc

#include "_cgo_export.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

/* Test calling panic from C.  This is what SWIG does.  */

extern void crosscall2(void (*fn)(void *, int), void *, int);
extern void _cgo_panic(void *, int);
extern void _cgo_allocate(void *, int);

void
callPanic(void)
{

After they are evaluated, the parameters of the call are passed by value to the function
and the called function begins execution.
The return parameters of the function are passed by value
back to the caller when the function returns.
</p>

<p>
Calling a <code>nil</code> function value
causes a <a href="#Run_time_panics">run-time panic</a>.
</p>

<p>

	{"byte", iotest.OneByteReader},
	{"half", iotest.HalfReader},
	{"data+err", iotest.DataErrReader},
	{"timeout", iotest.TimeoutReader},
}

// Call ReadString (which ends up calling everything else)
// to accumulate the text of a file.
func readLines(b *Reader) string {
	s := ""
	for {
		s1, err := b.ReadString('\n')
		if err == io.EOF {
			break
		}

	ctxFile
	ctxDecl
	ctxSpec
	ctxDefer
	ctxCall  // any function call other than ctxCall2
	ctxCall2 // function call whose result is assigned to two variables
	ctxSelector
)

// walk walks the AST x, calling visit(f, x, context) for each node.
func (f *File) walk(x interface{}, context astContext, visit func(*File, interface{}, astContext)) {
	visit(f, x, context)
	switch n := x.(type) {
	case *ast.Expr:

		check(t, testname+" (fill 4)", buf, s)
	}
	return s
}

func TestNewBuffer(t *testing.T) {
	buf := NewBuffer(testBytes)
	check(t, "NewBuffer", buf, testString)
}

var buf Buffer

// Calling NewBuffer and immediately shallow copying the Buffer struct
// should not result in any allocations.
// This can be used to reset the underlying []byte of an existing Buffer.
func TestNewBufferShallow(t *testing.T) {

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

//go:build gccgo

#include "_cgo_export.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

/* Test calling panic from C.  This is what SWIG does.  */

extern void _cgo_panic(const char *);
extern void *_cgo_allocate(size_t);

void
callPanic(void)
{
	_cgo_panic("panic from C");

	// "SCHILY.xattr." namespace.
	//
	// The following are semantically equivalent:
	//  h.Xattrs[key] = value
	//  h.PAXRecords["SCHILY.xattr."+key] = value
	//
	// When Writer.WriteHeader is called, the contents of Xattrs will take
	// precedence over those in PAXRecords.
	//
	// Deprecated: Use PAXRecords instead.
	Xattrs map[string]string

	// PAXRecords is a map of PAX extended header records.
	//

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "_cgo_export.h"

/* Test calling a Go function with multiple return values.  */

void
callMulti(void)
{
	struct multi_return result = multi();
	assert(strcmp(result.r0, "multi") == 0);
	assert(result.r1 == 0);
	free(result.r0);

//
// Buffer panics if it is called after scanning has started.
func (s *Scanner) Buffer(buf []byte, max int) {
	if s.scanCalled {
		panic("Buffer called after Scan")
	}
	s.buf = buf[0:cap(buf)]
	s.maxTokenSize = max
}

// Split sets the split function for the [Scanner].
// The default split function is [ScanLines].
//
// Split panics if it is called after scanning has started.