syscall_stackargs.go RawHistoryFolder

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: 2026 The Ebitengine Authors
3
4//go:build ppc64le || s390x
5
6package purego
7
8import "unsafe"
9
10// callbackArgs is the argument block passed from the assembly trampoline
11// to callbackWrap when C code calls a Go callback registered with NewCallback.
12// The assembly fills in the fields before calling callbackWrap, which uses
13// them to determine which Go function to invoke and where to read its
14// arguments from, and writes the return value back into result.
15//
16// callbackArgs is only used on Unix. On Windows, callbacks are handled by
17// the runtime's own callback mechanism, so this type is compiled but unused,
18// serving only as a stub to satisfy cross-platform compilation.
19type callbackArgs struct {
20	_     hostLayout
21	index uintptr
22	// args points to the argument block.
23	//
24	// The structure of the arguments goes
25	// float registers followed by the
26	// integer registers followed by the stack.
27	//
28	// This variable is treated as a contiguous
29	// block of memory containing all of the arguments
30	// for this callback.
31	args unsafe.Pointer
32	// Below are out-args from callbackWrap
33	result [1]uintptr
34	// stackArgs points to stack-passed arguments for architectures where
35	// they can't be made contiguous with register args (e.g., ppc64le).
36	// On other architectures, this is nil and stack args are read from
37	// the end of the args block.
38	stackArgs unsafe.Pointer
39}
40
41func (c *callbackArgs) stackFrame() unsafe.Pointer {
42	return c.stackArgs
43}