go build -o myatomic.a sync/atomic
exists myatomic.a
exec $GOBIN/isarchive myatomic.a
! exists atomic
! exists atomic.a
! exists atomic.exe

! go build -o whatever cmd/gofmt sync/atomic
stderr 'multiple packages'

-- go.mod --
module m

go 1.16
-- x.go --
package main

func main() {}
-- p.go --
package p
-- isarchive/isarchive.go --
package main

import (
	"bytes"
	"fmt"
	"io"

 * adding special code in cmd/link.
 * However, it will be called for every Go programs which has cgo.
 * Inside _rt0_ppc64_aix_lib(), runtime.isarchive is checked in order
 * to know if this program is a c-archive or a simple cgo program.
 * If it's not set, _rt0_ppc64_ax_lib() returns directly.
 */
static void libinit() {
	_rt0_ppc64_aix_lib();

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

//go:build unix

package runtime

func checkfds() {
	if islibrary || isarchive {
		// If the program is actually a library, presumably being consumed by
		// another program, we don't want to mess around with the file
		// descriptors.
		return
	}

	const (

//go:nosplit
//go:nowritebarrierrec
func initsig(preinit bool) {
	if !preinit {
		// It's now OK for signal handlers to run.
		signalsOK = true
	}

	// For c-archive/c-shared this is called by libpreinit with
	// preinit == true.
	if (isarchive || islibrary) && !preinit {
		return
	}

	for i := uint32(0); i < _NSIG; i++ {
		t := &sigtable[i]
		if t.flags == 0 || t.flags&_SigDefault != 0 {
			continue

	// signal stack on the main thread when not running in a
	// library. This can be removed when we are confident that all
	// FreeBSD users are running a patched kernel. See issue #15658.
	if gp := getg(); !isarchive && !islibrary && gp.m == &m0 && gp == gp.m.g0 {
		st := stackt{ss_flags: _SS_DISABLE}
		sigaltstack(&st, nil)
	}

	minitSignals()
}

// Called from dropm to undo the effect of an minit.
//

//
// It is nosplit for the same reason as exceptionhandler.
//
//go:nosplit
func lastcontinuehandler(info *exceptionrecord, r *context, gp *g) int32 {
	if islibrary || isarchive {
		// Go DLL/archive has been loaded in a non-go program.
		// If the exception does not originate from go, the go runtime
		// should not take responsibility of crashing the process.
		return _EXCEPTION_CONTINUE_SEARCH
	}

			t |= uint32(n) << tracebackShift
		}
	}
	// when C owns the process, simply exit'ing the process on fatal errors
	// and panics is surprising. Be louder and abort instead.
	if islibrary || isarchive {
		t |= tracebackCrash
	}

	t |= traceback_env

	atomic.Store(&traceback_cache, t)
}

// Poor mans 64-bit division.

				println("\t", hex(datap.ftab[j].entryoff), funcname(funcInfo{(*_func)(unsafe.Pointer(&datap.pclntable[datap.ftab[j].funcoff])), datap}))
			}
			if GOOS == "aix" && isarchive {
				println("-Wl,-bnoobjreorder is mandatory on aix/ppc64 with c-archive")
			}
			throw("invalid runtime symbol table")
		}
	}

	min := datap.textAddr(datap.ftab[0].entryoff)
	max := datap.textAddr(datap.ftab[nftab].entryoff)

//go:linkname goarm
var (
	goarm       uint8
	goarmsoftfp uint8
)

// Set by the linker so the runtime can determine the buildmode.
var (
	islibrary bool // -buildmode=c-shared
	isarchive bool // -buildmode=c-archive
)

// Must agree with internal/buildcfg.FramePointerEnabled.
const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"

	"path"
	"path/filepath"
	"sort"
	"strings"
	"time"
)

// An Archive describes an archive to write: a collection of files.
// Directories are implied by the files and not explicitly listed.
type Archive struct {
	Files []File
}

// A File describes a single file to write to an archive.
type File struct {
	Name string    // name in archive
	Time time.Time // modification time
	Mode fs.FileMode
	Size int64