Building Mac OS binaries
========================

This guide explains how to build Electrum binaries for macOS systems.


## 1. Building the binary

This needs to be done on a system running macOS or OS X. We use El Capitan (10.11.6) as building it
on High Sierra (or later)
makes the binaries incompatible with older versions. 


#### 1.1 Get Xcode

Building the QR code reader (CalinsQRReader) requires full Xcode (not just command line tools).

The last Xcode version compatible with El Capitan is Xcode 8.2.1

Get it from [here](https://developer.apple.com/download/more/).

Unfortunately, you need an "Apple ID" account.

After downloading, uncompress it.

Make sure it is the "selected" xcode (e.g.):

    sudo xcode-select -s $HOME/Downloads/Xcode.app/Contents/Developer/


#### 1.2 Build Electrum

    cd electrum
    ./contrib/osx/make_osx
    
This creates both a folder named Electrum.app and the .dmg file.


## 2. Building the image deterministically (WIP)
The usual way to distribute macOS applications is to use image files containing the 
application. Although these images can be created on a Mac with the built-in `hdiutil`,
they are not deterministic.

Instead, we use the toolchain that Bitcoin uses: genisoimage and libdmg-hfsplus.
These tools do not work on macOS, so you need a separate Linux machine (or VM).

Copy the Electrum.app directory over and install the dependencies, e.g.:

    apt install libcap-dev cmake make gcc faketime
    
Then you can just invoke `package.sh` with the path to the app:

    cd electrum
    ./contrib/osx/package.sh ~/Electrum.app/