// Length must match arg.Max in x_cgo_callers in runtime/cgo/gcc_traceback.c.
type cgoCallers [32]uintptr

// argset matches runtime/cgo/linux_syscall.c:argset_t
type argset struct {
	args   unsafe.Pointer
	retval uintptr
}

// wrapper for syscall package to call cgocall for libc (cgo) calls.
//
//go:linkname syscall_cgocaller syscall.cgocaller
//go:nosplit
//go:uintptrescapes

	traceback     uint8
	ncgocall      uint64        // number of cgo calls in total
	ncgo          int32         // number of cgo calls currently in progress
	cgoCallersUse atomic.Uint32 // if non-zero, cgoCallers in use temporarily
	cgoCallers    *cgoCallers   // cgo traceback if crashing in cgo call
	park          note
	alllink       *m // on allm
	schedlink     muintptr
	lockedg       guintptr

	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg == nil
	MOVQ	g_syscallsp(CX), CX
	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg.syscallsp == 0
	MOVQ	m_cgoCallers(AX), R8
	TESTQ	R8, R8
	JZ	sigtramp        // g.m.cgoCallers == nil
	MOVL	m_cgoCallersUse(AX), CX
	TESTL	CX, CX
	JNZ	sigtramp	// g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback

	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg == nil
	MOVQ	g_syscallsp(CX), CX
	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg.syscallsp == 0
	MOVQ	m_cgoCallers(AX), R8
	TESTQ	R8, R8
	JZ	sigtramp        // g.m.cgoCallers == nil
	MOVL	m_cgoCallersUse(AX), CX
	TESTL	CX, CX
	JNZ	sigtramp	// g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback

	MOVD	g_syscallsp(R7), R7
	CMP	$0, R7
	BEQ	sigtramp    // g.m.curg.syscallsp == 0
	MOVD	m_cgoCallers(R6), R7 // R7 is the fifth arg in C calling convention.
	CMP	$0, R7
	BEQ	sigtramp    // g.m.cgoCallers == nil
	MOVW	m_cgoCallersUse(R6), R8
	CMPW	$0, R8
	BNE	sigtramp    // g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback

	CBZ	R8, sigtramp    // g.m.curg == nil
	MOVD	g_syscallsp(R8), R7
	CBZ	R7,	sigtramp    // g.m.curg.syscallsp == 0
	MOVD	m_cgoCallers(R6), R4 // R4 is the fifth arg in C calling convention.
	CBZ	R4,	sigtramp    // g.m.cgoCallers == nil
	MOVW	m_cgoCallersUse(R6), R8
	CBNZW	R8, sigtramp    // g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback

	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg == nil
	MOVQ	g_syscallsp(CX), CX
	TESTQ	CX, CX
	JZ	sigtramp        // g.m.curg.syscallsp == 0
	MOVQ	m_cgoCallers(AX), R8
	TESTQ	R8, R8
	JZ	sigtramp        // g.m.cgoCallers == nil
	MOVL	m_cgoCallersUse(AX), CX
	TESTL	CX, CX
	JNZ	sigtramp	// g.m.cgoCallersUse != 0

	// Jump to a function in runtime/cgo.
	// That function, written in C, will call the user's traceback

// If the signal handler receives a SIGPROF signal on a non-Go thread,
// it tries to collect a traceback into sigprofCallers.
// sigprofCallersUse is set to non-zero while sigprofCallers holds a traceback.
var sigprofCallers cgoCallers
var sigprofCallersUse uint32

// sigprofNonGo is called if we receive a SIGPROF signal on a non-Go thread,
// and the signal handler collected a stack trace in sigprofCallers.

	} else if ret := cgocaller(cgo_libc_setgid, uintptr(gid)); ret != 0 {
		err = errnoErr(Errno(ret))
	}
	return
}

var cgo_libc_setregid unsafe.Pointer // non-nil if cgo linked.

func Setregid(rgid, egid int) (err error) {
	if cgo_libc_setregid == nil {
		if _, _, e1 := AllThreadsSyscall(sys_SETREGID, uintptr(rgid), uintptr(egid), 0); e1 != 0 {
			err = errnoErr(e1)
		}