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| author | Alberto Garc?a Hierro <alberto@garciahierro.com> | 2013-08-13 12:42:21 -0400 |
|---|---|---|
| committer | Alberto Garc?a Hierro <alberto@garciahierro.com> | 2013-08-13 12:42:21 -0400 |
| commit | e55042570b579081d643b066ec9649838df26d32 (patch) | |
| tree | 3f9035c4005d0ca3ed1f6f8ef08fb0863c347f83 /src/cmd/cgo/doc.go | |
| parent | 568afaa247474eeb25a79a0bdcaae9a072b46866 (diff) | |
| download | go-e55042570b579081d643b066ec9649838df26d32.tar.gz | |
cmd/cgo: Add support for C function pointers
* Add a new kind of Name, "fpvar" which stands for function pointer variable
* When walking the AST, find functions used as expressions and create a new Name object for them
* Track functions which are only used in expr contexts, and avoid generating bridge code for them
R=golang-dev, minux.ma, fullung, rsc, iant
CC=golang-dev
https://codereview.appspot.com/9835047
Committer: Russ Cox <rsc@golang.org>
Diffstat (limited to 'src/cmd/cgo/doc.go')
| -rw-r--r-- | src/cmd/cgo/doc.go | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/src/cmd/cgo/doc.go b/src/cmd/cgo/doc.go index 17f01c313..63737d4c2 100644 --- a/src/cmd/cgo/doc.go +++ b/src/cmd/cgo/doc.go @@ -76,6 +76,33 @@ function returns void). For example: n, err := C.sqrt(-1) _, err := C.voidFunc() +Calling C function pointers is currently not supported, however you can +declare Go variables which hold C function pointers and pass them +back and forth between Go and C. C code may call function pointers +received from Go. For example: + + package main + // typedef int (*intFunc) (); + // + // int + // bridge_int_func(intFunc f) + // { + // return f(); + // } + // + // int fortytwo() + // { + // return 42; + // } + import "C" + import "fmt" + + func main() { + f := C.intFunc(C.fortytwo) + fmt.Println(int(C.bridge_int_func(f))) + // Output: 42 + } + In C, a function argument written as a fixed size array actually requires a pointer to the first element of the array. C compilers are aware of this calling convention and adjust |