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doc/articles: use C90 standard functions in the cgo article.

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R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/9953043
This commit is contained in:
Shenghou Ma 2013-06-04 01:40:53 +08:00
parent 44b7d5b41a
commit 022818c142
3 changed files with 10 additions and 10 deletions
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12
doc/articles/c_go_cgo.html
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@ -11,8 +11,8 @@ single Go package.
<p>
To lead with an example, here's a Go package that provides two functions -
<code>Random</code> and <code>Seed</code> - that wrap C's <code>random</code>
and <code>srandom</code> functions.
<code>Random</code> and <code>Seed</code> - that wrap C's <code>rand</code>
and <code>srand</code> functions.
</p>
{{code "/doc/progs/cgo1.go" `/package rand/` `/END/`}}
@ -30,14 +30,14 @@ name space.
<p>
The <code>rand</code> package contains four references to the <code>C</code>
package: the calls to <code>C.random</code> and <code>C.srandom</code>, the
package: the calls to <code>C.rand</code> and <code>C.srand</code>, the
conversion <code>C.uint(i)</code>, and the <code>import</code> statement.
</p>
<p>
The <code>Random</code> function calls the standard C library's <code>random</code>
function and returns the result. In C, <code>random</code> returns a value of the
C type <code>long</code>, which cgo represents as the type <code>C.long</code>.
function and returns the result. In C, <code>rand</code> returns a value of the
C type <code>int</code>, which cgo represents as the type <code>C.int</code>.
It must be converted to a Go type before it can be used by Go code outside this
package, using an ordinary Go type conversion:
</p>
@ -54,7 +54,7 @@ the type conversion more explicitly:
<p>
The <code>Seed</code> function does the reverse, in a way. It takes a
regular Go <code>int</code>, converts it to the C <code>unsigned int</code>
type, and passes it to the C function <code>srandom</code>.
type, and passes it to the C function <code>srand</code>.
</p>
{{code "/doc/progs/cgo1.go" `/func Seed/` `/END/`}}

4
doc/progs/cgo1.go
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@ -12,12 +12,12 @@ import "C"
// STOP OMIT
func Random() int {
return int(C.random())
return int(C.rand())
}
// STOP OMIT
func Seed(i int) {
C.srandom(C.uint(i))
C.srand(C.uint(i))
}
// END OMIT

4
doc/progs/cgo2.go
View File

@ -11,13 +11,13 @@ package rand2
import "C"
func Random() int {
var r C.long = C.random()
var r C.int = C.rand()
return int(r)
}
// STOP OMIT
func Seed(i int) {
C.srandom(C.uint(i))
C.srand(C.uint(i))
}
// END OMIT