The short version: The #ifndef lines in the generated headers are preventing the inclusion of the Hello.objc.h content. (Which causes compile errors in a project that tries to use the framework.)

What version of Go are you using (go version)?

go version go1.7.4 darwin/amd64

What did you do?

1. Get and install current gomobile master (currently golang/mobile@c4d780f).

2. Compile the iOS bind example (golang/mobile/example/bind/ios).

Now look at the generated headers inside the Hello.framework directory.

Hello.h:

// Objective-C API for talking to the following Go packages
//
//      golang.org/x/mobile/example/bind/hello
//
// File is generated by gomobile bind. Do not edit.
#ifndef __Hello_H__
#define __Hello_H__

#include "Hello.objc.h"
#include "Universe.objc.h"

#endif

Hello.objc.h:

// Objective-C API for talking to golang.org/x/mobile/example/bind/hello Go package.
//   gobind -lang=objc golang.org/x/mobile/example/bind/hello
//
// File is generated by gobind. Do not edit.

#ifndef __Hello_H__
#define __Hello_H__

@import Foundation;
#include "Universe.objc.h"


FOUNDATION_EXPORT NSString* HelloGreetings(NSString* name);

#endif

Note that the two files have the same #ifndef/#define lines. This effectively removes the content of the Hello.objc.h file, causing errors when trying to use the framework.

I don't have a fix for this, but I believe the bug was introduced in golang/mobile@6a96d4c. (Perhaps it was always present with a default prefix.)

Workaround: Use the -prefix flag. The prefix will end up in the #ifndef symbol.