must be placed in preambles in other files, or in C source files.

# Passing pointers

Go is a garbage collected language, and the garbage collector needs to
know the location of every pointer to Go memory. Because of this,
there are restrictions on passing pointers between Go and C.

In this section the term Go pointer means a pointer to memory
allocated by Go (such as by using the & operator or calling the

</p>

<p>
Implementation restriction: Although numeric constants have arbitrary
precision in the language, a compiler may implement them using an
internal representation with limited precision.  That said, every
implementation must:
</p>

<ul>
	<li>Represent integer constants with at least 256 bits.</li>

	<li>Represent floating-point constants, including the parts of

  - type: textarea
    id: cost-description
    attributes:
      label: "Cost Description"
      description: "What is the cost of this proposal? (Every language change has a cost)"

  - type: input
    id: go-toolchain
    attributes:
      label: Changes to Go ToolChain

		return
	}
	// General address (with a few exceptions) looks like
	//	$sym±offset(SB)(reg)(index*scale)
	// Exceptions are:
	//
	//	R1
	//	offset
	//	$offset
	// Every piece is optional, so we scan left to right and what
	// we discover tells us where we are.

	// Prefix: $.
	var prefix rune
	switch tok := p.peek(); tok {
	case '$', '*':
		prefix = rune(tok)
		p.next()

</p>

<p>
Implementation restriction: Although numeric constants have arbitrary
precision in the language, a compiler may implement them using an
internal representation with limited precision.  That said, every
implementation must:
</p>

<ul>
	<li>Represent integer constants with at least 256 bits.</li>

	<li>Represent floating-point constants, including the parts of

		// field directly themselves. All other approaches sets UTC.
		fh.ModifiedDate, fh.ModifiedTime = timeToMsDosTime(fh.Modified)

		// Use "extended timestamp" format since this is what Info-ZIP uses.
		// Nearly every major ZIP implementation uses a different format,
		// but at least most seem to be able to understand the other formats.
		//
		// This format happens to be identical for both local and central header

	curr fileReader // Reader for current file entry
	blk  block      // Buffer to use as temporary local storage

	// err is a persistent error.
	// It is only the responsibility of every exported method of Reader to
	// ensure that this error is sticky.
	err error
}

type fileReader interface {
	io.Reader
	fileState

	WriteTo(io.Writer) (int64, error)
}

sending an item acquires the semaphore, and receiving an item releases
the semaphore.
This is a common idiom for limiting concurrency.
</p>

<p>
This program starts a goroutine for every entry in the work list, but the
goroutines coordinate using the <code>limit</code> channel to ensure
that at most three are running work functions at a time.
</p>

<pre>
var limit = make(chan int, 3)