cmd/go: document that functions are exported by cgo

The buildmode docs mention exported functions, but don't say anything
about how to export them.  Mention the cgo tool to make this somewhat
clearer.

Fixes #11955.

Change-Id: Ie5420445daa87f5aceec6ad743465d5d32d0a786
Reviewed-on: https://go-review.googlesource.com/13080
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 044e776ec047186825d5dbd96c893454dd23573f..0f610ddd9a95e8d3b8ed35a6e92e6dcd03daca1f 100644 (file)
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -781,14 +781,14 @@ are:
        -buildmode=c-archive
                Build the listed main package, plus all packages it imports,
                into a C archive file. The only callable symbols will be those
-               functions marked as exported. Requires exactly one main package
-               to be listed.
+               functions marked as exported by the cgo tool. Requires exactly
+               one main package to be listed.
 
        -buildmode=c-shared
                Build the listed main packages, plus all packages that they
                import, into C shared libraries. The only callable symbols will
-               be those functions marked as exported. Non-main packages are
-               ignored.
+               be those functions marked as exported by the cgo tool. Non-main
+               packages are ignored.
 
        -buildmode=default
                Listed main packages are built into executables and listed

diff --git a/src/cmd/go/help.go b/src/cmd/go/help.go
index 591c2f4a0739be54b35ae8f906f67cb893d708bd..6142874e0bd23be20359ee1d21fb2b3788fdd434 100644 (file)
--- a/src/cmd/go/help.go
+++ b/src/cmd/go/help.go
@@ -548,14 +548,14 @@ are:
        -buildmode=c-archive
                Build the listed main package, plus all packages it imports,
                into a C archive file. The only callable symbols will be those
-               functions marked as exported. Requires exactly one main package
-               to be listed.
+               functions marked as exported by the cgo tool. Requires exactly
+               one main package to be listed.
 
        -buildmode=c-shared
                Build the listed main packages, plus all packages that they
                import, into C shared libraries. The only callable symbols will
-               be those functions marked as exported. Non-main packages are
-               ignored.
+               be those functions marked as exported by the cgo tool. Non-main
+               packages are ignored.
 
        -buildmode=default
                Listed main packages are built into executables and listed