# OpenBSD Build Guide

**Updated for OpenBSD [7.5](https://www.openbsd.org/75.html)**

This guide describes how to build bitcoind, command-line utilities, and GUI on OpenBSD.

## Preparation

### 1. Install Required Dependencies
Run the following as root to install the base dependencies for building.

```bash
pkg_add bash git gmake libevent libtool boost
# Select the newest version of the following packages:
pkg_add autoconf automake python
```

See [dependencies.md](dependencies.md) for a complete overview.

### 2. Clone Bitcoin Repo
Clone the Bitcoin Core repository to a directory. All build scripts and commands will run from this directory.
``` bash
git clone https://github.com/bitcoin/bitcoin.git
```

### 3. Install Optional Dependencies

#### Wallet Dependencies

It is not necessary to build wallet functionality to run either `bitcoind` or `bitcoin-qt`.

###### Descriptor Wallet Support

`sqlite3` is required to support [descriptor wallets](descriptors.md).

``` bash
pkg_add sqlite3
```

###### Legacy Wallet Support
BerkeleyDB is only required to support legacy wallets.

It is recommended to use Berkeley DB 4.8. You cannot use the BerkeleyDB library
from ports. However you can build it yourself, [using depends](/depends).

Refer to [depends/README.md](/depends/README.md) for detailed instructions.

```bash
gmake -C depends NO_BOOST=1 NO_LIBEVENT=1 NO_QT=1 NO_SQLITE=1 NO_NATPMP=1 NO_UPNP=1 NO_ZMQ=1 NO_USDT=1
...
to: /path/to/bitcoin/depends/x86_64-unknown-openbsd
```

Then set `BDB_PREFIX`:

```bash
export BDB_PREFIX="/path/to/bitcoin/depends/x86_64-unknown-openbsd"
```

#### GUI Dependencies
###### Qt5

Bitcoin Core includes a GUI built with the cross-platform Qt Framework. To compile the GUI, Qt 5 is required.

```bash
pkg_add qtbase qttools
```

###### libqrencode

The GUI can encode addresses in a QR Code. To build in QR support for the GUI, install `libqrencode`. Skip if not using the GUI or don't want QR code functionality.
```bash
pkg_add libqrencode
```
---

#### Notifications
###### ZeroMQ

Bitcoin Core can provide notifications via ZeroMQ. If the package is installed, support will be compiled in.
```bash
pkg_add zeromq
```

## Building Bitcoin Core

**Important**: Use `gmake` (the non-GNU `make` will exit with an error).

Preparation:
```bash

# Adapt the following for the version you installed (major.minor only):
export AUTOCONF_VERSION=2.71
export AUTOMAKE_VERSION=1.16

./autogen.sh
```

### 1. Configuration

There are many ways to configure Bitcoin Core, here are a few common examples:

##### Descriptor Wallet and GUI:
This enables the GUI and descriptor wallet support, assuming `sqlite` and `qt5` are installed.

```bash
./configure MAKE=gmake
```

##### Descriptor & Legacy Wallet. No GUI:
This enables support for both wallet types and disables the GUI:

```bash
./configure --with-gui=no \
    BDB_LIBS="-L${BDB_PREFIX}/lib -ldb_cxx-4.8" \
    BDB_CFLAGS="-I${BDB_PREFIX}/include" \
    MAKE=gmake
```

### 2. Compile
**Important**: Use `gmake` (the non-GNU `make` will exit with an error).

```bash
gmake # use "-j N" for N parallel jobs
gmake check # Run tests if Python 3 is available
```

## Resource limits

If the build runs into out-of-memory errors, the instructions in this section
might help.

The standard ulimit restrictions in OpenBSD are very strict:
```bash
data(kbytes)         1572864
```

This is, unfortunately, in some cases not enough to compile some `.cpp` files in the project,
(see issue [#6658](https://github.com/bitcoin/bitcoin/issues/6658)).
If your user is in the `staff` group the limit can be raised with:
```bash
ulimit -d 3000000
```
The change will only affect the current shell and processes spawned by it. To
make the change system-wide, change `datasize-cur` and `datasize-max` in
`/etc/login.conf`, and reboot.