The `GOARM64` environment variable defaults to `v8.0`.

### RISC-V {#riscv}

<!-- go.dev/issue/61476, CL 541135 -->
Go 1.23 introduces a new `GORISCV64` environment variable, which selects the [RISC-V user-mode application profile](https://github.com/riscv/riscv-profiles/blob/main/src/profiles.adoc) for which to compile. Allowed values are `rva20u64` and `rva22u64`.

//
//export RunGoroutines
func RunGoroutines() {
	for i := 0; i < 4; i++ {
		go func() {
			runtime.LockOSThread()
			select {}
		}()
	}
}

// Block blocks the current thread while running Go code.
//
//export Block
func Block() {
	select {}
}

var P *byte

// TestSEGV makes sure that an invalid address turns into a run-time Go panic.
//
//export TestSEGV
func TestSEGV() {

#!/bin/sh
# This uses the latest available iOS SDK, which is recommended.
# To select a specific SDK, run 'xcodebuild -showsdks'
# to see the available SDKs and replace iphoneos with one of them.
if [ "$GOARCH" == "arm64" ]; then
	SDK=iphoneos
	PLATFORM=ios
	CLANGARCH="arm64"
else
	SDK=iphonesimulator
	PLATFORM=ios-simulator
	CLANGARCH="x86_64"
fi

SDK_PATH=`xcrun --sdk $SDK --show-sdk-path`
export IPHONEOS_DEPLOYMENT_TARGET=5.1

// 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.

// Tests that cgo detects invalid pointer passing at runtime.

package errorstest

import (
	"bytes"
	"flag"
	"fmt"
	"internal/testenv"
	"os"
	"os/exec"
	"path/filepath"
	"slices"
	"strings"
	"sync/atomic"
	"testing"
)

	// emulate an exceedingly slow package initialization function
	time.Sleep(100 * time.Millisecond)
	initCh <- 42
}

func main() {
	ranMain = true
}

//export DidInitRun
func DidInitRun() bool {
	select {
	case x := <-initCh:
		if x != 42 {
			// Just in case initCh was not correctly made.
			println("want init value of 42, got: ", x)
			syscall.Exit(2)
		}
		return true
	default:
		return false
	}
}

	    statement</a>.</li>
	</ul>
</li>

<li>
	A <a href="#Select_statements">"select" statement</a> in which:
	<ul>
	<li>there are no "break" statements referring to the "select" statement, and</li>
	<li>the statement lists in each case, including the default if present,
	    end in a terminating statement.</li>
	</ul>
</li>

<li>

	Example:
	//go:cgo_ldflag "-lpthread"
	//go:cgo_ldflag "-L/usr/local/sqlite3/lib"

A package compiled with cgo will include directives for both
internal and external linking; the linker will select the appropriate
subset for the chosen linking mode.

Example

As a simple example, consider a package that uses cgo to call C.sin.
The following code will be generated by cgo:

	// compiled by gc

	return 0, nil
}

func TestZeroReader(t *testing.T) {
	var z zeroReader
	r := NewReader(z)

	c := make(chan error)
	go func() {
		_, err := r.ReadByte()
		c <- err
	}()

	select {
	case err := <-c:
		if err == nil {
			t.Error("error expected")
		} else if err != io.ErrNoProgress {
			t.Error("unexpected error:", err)
		}
	case <-time.After(time.Second):

pkg syscall (freebsd-riscv64), func RouteRIB(int, int) ([]uint8, error) #53466
pkg syscall (freebsd-riscv64), func Seek(int, int64, int) (int64, error) #53466
pkg syscall (freebsd-riscv64), func Select(int, *FdSet, *FdSet, *FdSet, *Timeval) error #53466
pkg syscall (freebsd-riscv64), func Sendfile(int, int, *int64, int) (int, error) #53466

// signals when non-Go signals are raised.

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/select.h>

#include "libgo2.h"

int *nilp;

int main(int argc, char** argv) {
	int verbose;
	int test;

	if (argc < 2) {
		printf("Missing argument\n");
		return 1;
	}

	test = atoi(argv[1]);