// fs.FileInfo.
// Because fs.FileInfo's Name method returns only the base name of
// the file it describes, it may be necessary to modify the Name field
// of the returned header to provide the full path name of the file.
// If compression is desired, callers should set the FileHeader.Method
// field; it is unset by default.
func FileInfoHeader(fi fs.FileInfo) (*FileHeader, error) {
	size := fi.Size()

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

that assembly programming is a fraught endeavor.
(Exception: the <code>g</code> register renaming on ARM.)
</p>

<p>
In Go object files and binaries, the full name of a symbol is the
package path followed by a period and the symbol name:
<code>fmt.Printf</code> or <code>math/rand.Int</code>.
Because the assembler's parser treats period and slash as punctuation,

then an `api/next` file with the line

    pkg net/http, function F #12345

should have a corresponding file named `doc/next/6-stdlib/99-minor/net/http/12345.md`.
At a minimum, that file should contain either a full sentence or a TODO,
ideally referring to a person with the responsibility to complete the note.

Use the following forms in your markdown:

// given ASCII character in the set. The 128-bits of the lower 16 bytes,
// starting with the least-significant bit of the lowest word to the
// most-significant bit of the highest word, map to the full range of all
// 128 ASCII characters. The 128-bits of the upper 16 bytes will be zeroed,
// ensuring that any non-ASCII character will be reported as not in the set.
// This allocates a total of 32 bytes even though the upper half

		return 0, false
	}
	r, ok := p.arch.RegisterNumber(name, int16(num))
	if !ok {
		p.errorf("illegal register %s(%d)", name, r)
		return 0, false
	}
	return r, true
}

// register parses a full register reference where there is no symbol present (as in 4(R0) or R(10) but not sym(SB))
// including forms involving multiple registers such as R1:R2.

succeeds only when both a sender and receiver are ready. Otherwise, the channel
is buffered and communication succeeds without blocking if the buffer
is not full (sends) or not empty (receives).
A <code>nil</code> channel is never ready for communication.
</p>

<p>
A channel may be closed with the built-in function
<a href="#Close"><code>close</code></a>.

func (b *Reader) ReadBytes(delim byte) ([]byte, error) {
	full, frag, n, err := b.collectFragments(delim)
	// Allocate new buffer to hold the full pieces and the fragment.
	buf := make([]byte, n)
	n = 0
	// Copy full pieces and fragment in.
	for i := range full {
		n += copy(buf[n:], full[i])
	}
	copy(buf[n:], frag)
	return buf, err
}

			t.Errorf("want error matching %s, got %s", wantErr, err)
		}
		// And it should flush all output (even if it looks
		// like we may be getting an exit code)
		if got := out.String(); text != got {
			t.Errorf("want full output %q, got %q", text, got)
		}
	}
	wantErr = regexp.MustCompile("^no exit code")
	check("abc")
	check("exitcode")
	check("exitcode=")
	check("exitcode=123\n")

}

func (f *exitCodeFilter) Finish() (int, error) {
	// f.buf could be empty, contain a partial match of exitRe, or
	// contain a full match.
	b := f.buf.Bytes()
	defer f.buf.Reset()
	match := f.exitRe.FindSubmatch(b)
	if len(match) < 2 || match[1] == nil {
		// Not a full match. Flush.
		if _, err := f.w.Write(b); err != nil {
			return 0, err
		}
		return 0, fmt.Errorf("no exit code (in %q)", string(b))
	}