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authorIan Lance Taylor <iant@golang.org>2010-08-23 17:50:30 -0700
committerIan Lance Taylor <iant@golang.org>2010-08-23 17:50:30 -0700
commitf62b3c8fe9f78819ef7116e13132b6dd5056133c (patch)
tree651605ff2d94a3d17c31c33dc540bba2b904c200 /doc/gccgo_install.html
parentf7e4f45821462efffd0ccb7bc26839fccc07d059 (diff)
downloadgo-f62b3c8fe9f78819ef7116e13132b6dd5056133c.tar.gz
doc: Update gccgo information for recent changes.
R=r CC=golang-dev http://codereview.appspot.com/1941052
Diffstat (limited to 'doc/gccgo_install.html')
-rw-r--r--doc/gccgo_install.html30
1 files changed, 15 insertions, 15 deletions
diff --git a/doc/gccgo_install.html b/doc/gccgo_install.html
index a01a5468e..e4e471b76 100644
--- a/doc/gccgo_install.html
+++ b/doc/gccgo_install.html
@@ -224,12 +224,9 @@ gccgo -o main main.o mypackage.o # Explicitly links with mypackage.o
<p>
Some Go features are not yet implemented in <code>gccgo</code>. As of
-2009-11-06, the following are not implemented:
+2010-08-23, the following are not implemented:
<ul>
-<li>Garbage collection is not implemented. There is no way to free memory.
- Thus long running programs are not supported.
-
<li>goroutines are implemented as NPTL threads. If you can not use
the gold linker as described above, they are created with a fixed
stack size, and the number of goroutines that may be created at
@@ -263,14 +260,13 @@ Pointers in Go are pointers in C. A Go <code>struct</code> is the same as C
<code>struct</code> with the same fields and types.
<p>
-The Go <code>string</code> type is a pointer to a structure.
-The current definition is
-(this is <b style="color: red;">expected to change</b>):
+The Go <code>string</code> type is currently defined as a two-element
+structure (this is <b style="color: red;">subject to change</b>):
<pre>
struct __go_string {
- size_t __length;
- unsigned char __data[];
+ const unsigned char *__data;
+ int __length;
};
</pre>
@@ -310,9 +306,10 @@ when the functions have equivalent types.
<p>
Go <code>interface</code>, <code>channel</code>, and <code>map</code>
-types have no corresponding C type (they roughly correspond to pointers
-to structs in C, but the structs are deliberately undocumented). C
-<code>enum</code> types correspond to some Go type, but precisely
+types have no corresponding C type (<code>interface</code> is a
+two-element struct and <code>channel</code> and <code>map</code> are
+pointers to structs in C, but the structs are deliberately undocumented). C
+<code>enum</code> types correspond to some integer type, but precisely
which one is difficult to predict in general; use a cast. C <code>union</code>
types have no corresponding Go type. C <code>struct</code> types containing
bitfields have no corresponding Go type. C++ <code>class</code> types have
@@ -359,12 +356,15 @@ i := c_open(&amp;name[0], os.O_RDONLY, 0);
<p>
The name of Go functions accessed from C is subject to change. At present
the name of a Go function that does not have a receiver is
-<code>package.Functionname</code>. To call it from C you must set the
-name using a <code>gcc</code> extension similar to the <code>gccgo</code>
+<code>prefix.package.Functionname</code>. The prefix is set by
+the <code>-fgo-prefix</code> option used when the package is compiled;
+if the option is not used, the default is simply <code>go</code>.
+To call the function from C you must set the name using
+a <code>gcc</code> extension similar to the <code>gccgo</code>
extension.
<pre>
-extern int go_function(int) __asm__ ("mypackage.Function");
+extern int go_function(int) __asm__ ("myprefix.mypackage.Function");
</pre>
<h3 id="Automatic_generation_of_Go_declarations_from_C_source_code">