qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-22 04:24:39 -07:00
Code Releases Activity

go spec: arguments for append may overlap

Browse Source 
Fixes #4142.

R=rsc, r, iant, ken, remyoudompheng
CC=golang-dev
https://golang.org/cl/6567062
This commit is contained in:
Robert Griesemer 2012-09-28 15:55:38 -07:00
parent 7c8e26ee2f
commit 0c494718af
1 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
doc/go_spec.html
View File

@ -1,6 +1,6 @@
<!--{
"Title": "The Go Programming Language Specification",
"Subtitle": "Version of September 26, 2012",
"Subtitle": "Version of September 28, 2012",
"Path": "/ref/spec"
}-->
@ -4903,7 +4903,10 @@ m := make(map[string]int, 100) // map with initial space for 100 elements
<h3 id="Appending_and_copying_slices">Appending to and copying slices</h3>
<p>
Two built-in functions assist in common slice operations.
The built-in functions <code>append</code> and <code>copy</code> assist in
common slice operations.
For both functions, the result is independent of whether the memory referenced
by the arguments overlaps.
</p>
<p>
@ -4934,21 +4937,22 @@ slice may refer to a different underlying array.
<pre>
s0 := []int{0, 0}
s1 := append(s0, 2) // append a single element s1 == []int{0, 0, 2}
s2 := append(s1, 3, 5, 7) // append multiple elements s2 == []int{0, 0, 2, 3, 5, 7}
s3 := append(s2, s0...) // append a slice s3 == []int{0, 0, 2, 3, 5, 7, 0, 0}
s1 := append(s0, 2) // append a single element s1 == []int{0, 0, 2}
s2 := append(s1, 3, 5, 7) // append multiple elements s2 == []int{0, 0, 2, 3, 5, 7}
s3 := append(s2, s0...) // append a slice s3 == []int{0, 0, 2, 3, 5, 7, 0, 0}
s4 := append(s3[3:6], s3[2:]...) // append overlapping slice s4 == []int{3, 5, 7, 2, 3, 5, 7, 0, 0}
var t []interface{}
t = append(t, 42, 3.1415, "foo") t == []interface{}{42, 3.1415, "foo"}
t = append(t, 42, 3.1415, "foo") t == []interface{}{42, 3.1415, "foo"}
var b []byte
b = append(b, "bar"...) // append string contents b == []byte{'b', 'a', 'r' }
b = append(b, "bar"...) // append string contents b == []byte{'b', 'a', 'r' }
</pre>
<p>
The function <code>copy</code> copies slice elements from
a source <code>src</code> to a destination <code>dst</code> and returns the
number of elements copied. Source and destination may overlap.
number of elements copied.
Both arguments must have <a href="#Type_identity">identical</a> element type <code>T</code> and must be
<a href="#Assignability">assignable</a> to a slice of type <code>[]T</code>.
The number of elements copied is the minimum of