dash/doc/build-openbsd.md

OpenBSD build guide
======================
(updated for OpenBSD 5.7)

This guide describes how to build dashd and command-line utilities on OpenBSD.

As OpenBSD is most common as a server OS, we will not bother with the GUI.

Preparation
-------------

Run the following as root to install the base dependencies for building:

```bash
pkg_add gmake libtool libevent
pkg_add autoconf # (select highest version, e.g. 2.69)
pkg_add automake # (select highest version, e.g. 1.15)
pkg_add python # (select version 2.7.x, not 3.x)
ln -sf /usr/local/bin/python2.7 /usr/local/bin/python2
```

The default C++ compiler that comes with OpenBSD 5.7 is g++ 4.2. This version is old (from 2007), and is not able to compile the current version of Dash Core. It is possible to patch it up to compile, but with the planned transition to C++11 this is a losing battle. So here we will be installing a newer compiler.

GCC
-------

You can install a newer version of gcc with:

```bash
pkg_add g++ # (select newest 4.x version, e.g. 4.9.2)
```

This compiler will not overwrite the system compiler, it will be installed as `egcc` and `eg++` in `/usr/local/bin`.

### Building boost

Do not use `pkg_add boost`! The boost version installed thus is compiled using the `g++` compiler not `eg++`, which will result in a conflict between `/usr/local/lib/libestdc++.so.XX.0` and `/usr/lib/libstdc++.so.XX.0`, resulting in a test crash:

    test_dash:/usr/lib/libstdc++.so.57.0: /usr/local/lib/libestdc++.so.17.0 : WARNING: symbol(_ZN11__gnu_debug17_S_debug_me ssagesE) size mismatch, relink your program
    ...
    Segmentation fault (core dumped)

This makes it necessary to build boost, or at least the parts used by Dash Core, manually:

```
# Pick some path to install boost to, here we create a directory within the dash directory
BITCOIN_ROOT=$(pwd)
BOOST_PREFIX="${BITCOIN_ROOT}/boost"
mkdir -p $BOOST_PREFIX

# Fetch the source and verify that it is not tampered with
wget http://heanet.dl.sourceforge.net/project/boost/boost/1.59.0/boost_1_59_0.tar.bz2
echo '727a932322d94287b62abb1bd2d41723eec4356a7728909e38adb65ca25241ca  boost_1_59_0.tar.bz2' | sha256 -c
# MUST output: (SHA256) boost_1_59_0.tar.bz2: OK
tar -xjf boost_1_59_0.tar.bz2

# Boost 1.59 needs two small patches for OpenBSD
cd boost_1_59_0
# Also here: https://gist.githubusercontent.com/laanwj/bf359281dc319b8ff2e1/raw/92250de8404b97bb99d72ab898f4a8cb35ae1ea3/patch-boost_test_impl_execution_monitor_ipp.patch
patch -p0 < /usr/ports/devel/boost/patches/patch-boost_test_impl_execution_monitor_ipp
# https://github.com/boostorg/filesystem/commit/90517e459681790a091566dce27ca3acabf9a70c
sed 's/__OPEN_BSD__/__OpenBSD__/g' < libs/filesystem/src/path.cpp > libs/filesystem/src/path.cpp.tmp
mv libs/filesystem/src/path.cpp.tmp libs/filesystem/src/path.cpp

# Build w/ minimum configuration necessary for dash
echo 'using gcc : : eg++ : <cxxflags>"-fvisibility=hidden -fPIC" <linkflags>"" <archiver>"ar" <striper>"strip"  <ranlib>"ranlib" <rc>"" : ;' > user-config.jam
config_opts="runtime-link=shared threadapi=pthread threading=multi link=static variant=release --layout=tagged --build-type=complete --user-config=user-config.jam -sNO_BZIP2=1"
./bootstrap.sh --without-icu --with-libraries=chrono,filesystem,program_options,system,thread,test
./b2 -d2 -j2 -d1 ${config_opts} --prefix=${BOOST_PREFIX} stage
./b2 -d0 -j4 ${config_opts} --prefix=${BOOST_PREFIX} install
```

### Building BerkeleyDB

BerkeleyDB is only necessary for the wallet functionality. To skip this, pass `--disable-wallet` to `./configure`.

See "Berkeley DB" in [build_unix.md](build_unix.md) for instructions on how to build BerkeleyDB 4.8.
You cannot use the BerkeleyDB library from ports, for the same reason as boost above (g++/libstd++ incompatibility).

```bash
# Pick some path to install BDB to, here we create a directory within the dash directory
BITCOIN_ROOT=$(pwd)
BDB_PREFIX="${BITCOIN_ROOT}/db4"
mkdir -p $BDB_PREFIX

# Fetch the source and verify that it is not tampered with
wget 'http://download.oracle.com/berkeley-db/db-4.8.30.NC.tar.gz'
echo '12edc0df75bf9abd7f82f821795bcee50f42cb2e5f76a6a281b85732798364ef  db-4.8.30.NC.tar.gz' | sha256 -c
# MUST output: (SHA256) db-4.8.30.NC.tar.gz: OK
tar -xzf db-4.8.30.NC.tar.gz

# Build the library and install to specified prefix
cd db-4.8.30.NC/build_unix/
#  Note: Do a static build so that it can be embedded into the executable, instead of having to find a .so at runtime
../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIX CC=egcc CXX=eg++ CPP=ecpp
make install
```

### Building Dash Core

**Important**: use `gmake`, not `make`. The non-GNU `make` will exit with a horrible error.

Preparation:
```bash
export AUTOCONF_VERSION=2.69 # replace this with the autoconf version that you installed
export AUTOMAKE_VERSION=1.15 # replace this with the automake version that you installed
./autogen.sh
```
Make sure `BDB_PREFIX` and `BOOST_PREFIX` are set to the appropriate paths from the above steps.

To configure with wallet:
```bash
./configure --with-gui=no --with-boost=$BOOST_PREFIX \
    CC=egcc CXX=eg++ CPP=ecpp \
    LDFLAGS="-L${BDB_PREFIX}/lib/" CPPFLAGS="-I${BDB_PREFIX}/include/"
```

To configure without wallet:
```bash
./configure --disable-wallet --with-gui=no --with-boost=$BOOST_PREFIX \
    CC=egcc CXX=eg++ CPP=ecpp
```

Build and run the tests:
```bash
gmake
gmake check
```

Clang (not currently working)
------------------------------

Using a newer g++ results in linking the new code to a new libstdc++.
Libraries built with the old g++, will still import the old library.
This gives conflicts, necessitating rebuild of all C++ dependencies of the application.

With clang this can - at least theoretically - be avoided because it uses the
base system's libstdc++.

```bash
pkg_add llvm boost
```

```bash
./configure --disable-wallet --with-gui=no CC=clang CXX=clang++
gmake
```

However, this does not appear to work. Compilation succeeds, but link fails
with many 'local symbol discarded' errors:

    local symbol 150: discarded in section `.text._ZN10tinyformat6detail14FormatIterator6finishEv' from libbitcoin_util.a(libbitcoin_util_a-random.o)
    local symbol 151: discarded in section `.text._ZN10tinyformat6detail14FormatIterator21streamStateFromFormatERSoRjPKcii' from libbitcoin_util.a(libbitcoin_util_a-random.o)
    local symbol 152: discarded in section `.text._ZN10tinyformat6detail12convertToIntIA13_cLb0EE6invokeERA13_Kc' from libbitcoin_util.a(libbitcoin_util_a-random.o)

According to similar reported errors this is a binutils (ld) issue in 2.15, the
version installed by OpenBSD 5.7:

- http://openbsd-archive.7691.n7.nabble.com/UPDATE-cppcheck-1-65-td248900.html
- https://llvm.org/bugs/show_bug.cgi?id=9758

There is no known workaround for this.