mirror of
https://github.com/golang/go
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66 lines
1.9 KiB
HTML
66 lines
1.9 KiB
HTML
<!--{
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"Title": "Go 1.1 Release Notes",
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"Path": "/doc/go1.1",
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"Template": true
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}-->
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<h2 id="introduction">Introduction to Go 1.1</h2>
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TODO
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- overview
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- link back to Go 1 and also Go 1 Compatibility docs.
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<h2 id="language">Changes to the language</h2>
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TODO
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<h2 id="impl">Changes to the implementations and tools</h2>
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TODO: more
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<h3 id="int">Size of int on 64-bit platforms</h3>
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<p>
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The language allows the implementation to choose whether the <code>int</code> type and <code>uint</code> types are 32 or 64 bits. Previous Go implementations made <code>int</code> and <code>uint</code> 32 bits on all systems. Both the gc and gccgo implementations (TODO: check that gccgo does) <a href="http://golang.org/issue/2188">now make <code>int</code> and <code>uint</code> 64 bits on 64-bit platforms such as AMD64/x86-64</a>.
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Among other things, this enables the allocation of slices with
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more than 2 billion elements on 64-bit platforms.
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</p>
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<p>
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<em>Updating</em>:
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Most programs will be unaffected by this change.
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Because Go does not allow implicit conversions between distinct
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<a href="/ref/spec#Numeric_types">numeric types</a>,
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no programs will stop compiling due to this change.
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However, programs that contain implicit assumptions
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that <code>int</code> is only 32 bits may change behavior.
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For example, this code prints a positive number on 64-bit systems and
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a negative one on 32-bit systems:
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<pre>
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x := ^uint32(0) // x is 0xffffffff
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i := int(x) // i is -1 on 32-bit systems, 0xffffffff on 64-bit
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fmt.Println(i)
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</pre>
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<p>Portable code intending 32-bit sign extension (yielding -1 on all systems)
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would instead say:
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</p>
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<pre>
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i := int(int32(x))
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</pre>
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<h3 id="asm">Assembler</h3>
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<p>
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Due to the <a href="#int">int</a> and TODO: OTHER changes,
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the placement of function arguments on the stack has changed.
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Functions written in assembly will need to be revised at least
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to adjust frame pointer offsets.
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</p>
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<h2 id="library">Changes to the standard library</h2>
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TODO
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