Building GPSD from source

C99 conformance is required in the compiler. The C code depends on one C11 feature (supported by GCC, clang, and pretty much any C compiler that also speaks C++): anonymous unions. We could eliminate these, but the cost would be source-level interface breakage if we have to move certain structure members in and out of unions.

Some portions of the code using shared-memory segments are improved by the C11 stdatomic.h features for lockless concurrency. These are: the SHM export mode in shmexport.c, the code for writing clock corrections to NTP in ntpshmwrite.c, and the code for reading NTP corrections in ntpshmread.c. These features have been supported in GCC since 4.7 and clang since 3.1.

GPSD is normally built and tested with GCC. Do not compile with a version older than 4.1.1; there are several known issues with older versions, including (a) non-standards-conformant floating-point generation that messes up regression testing, (b) a compiler bug affecting RTCM2 code generation, (c) the option -Wno-missing-field-initializers is unavailable, leading to a flood of warnings (this is due to generated code and cannot be fixed).

clang produces a gpsd that passes all regression tests.

If you get a build failure including the text "error adding symbols: DSO missing from command line" or the complaint "ERROR: CC doesn’t work", you nay have tripped over stale data in the builder’s configuration cache. Clean the directory with "scons -c" then manually remove .sconsign.*dblite and retry your build.

You will need Python 2.x at minor version 6 or later or Python 3 at at minor version 3 or later.

While Python is required to build GPSD from source (the build uses some code generators in Python), it is not required to run the service daemon. In particular, you can cross-compile onto an embedded system without having to take Python with you.

scons finds the python used for scons separately from the python that should be used for the target. It seems to look for the target python as "python", which as above is supposed to exist per python norms. However, some packaging systems avoid a bare python, preferring to bind a program to a particular release as it is built. On systems without a "python" command, invoking scons as: scons target_python=python3.7 seems to help.

You will need both basic Python and (if your package system makes the distinction) the Python development package used for building C extensions. Usually these are called "python" and "python-dev". You will know you are missing the latter if your compilation fails because of a missing Python.h.

The xgps and xgpsspeed clients will only be installed if these Python extensions are installed:

On Gentoo systems those packages are named:

The ubxtool and zerk clients will only be usable in direct-serial mode if this Python extension is installed:

On Gentoo systems that package is named:

The *gpsplot( client requires Matplotlib to do its job of creating dynamic plots.

On Gentoo systems that package is named:

You will need scons version 2.3.0 (from 2013-03-02) or later to build the code. (Note that there is no evidence of recent testing of scons older than about 3.1.)

Having the following optional components on your system will enable various additional capabilities and extensions:

If you have libusb-1.0.0 or later, the GPSD build will autodetect this and use it to discover Garmin USB GPSes, rather than groveling through /proc/bus/usb/devices (which has been deprecated by the Linux kernel team).

On Gentoo systems those packages are named:

Debian/Ubuntu, and Fedora/RHEL, derived systems often split packages into binary, and development packages. Raspbian is Debian derived. This does not apply to Gentoo derived systems.

These development packages usually have a "-dev" suffix. Installing the development package usually installs the binary package for you.

The development Debian/Ubuntu/Raspbian pacakages are:

The development Fedora/RHEL packages are:

You can build libQgpsmm if you have Qt (specifically QtCore and QtNetwork modules) version 4.5.3 or higher. You will also need a C++ compiler supported by Qt (tested on GCC 4.4.0/mingw on Windows and GCC 4.1.2 on linux). Please refer to Qt’s documentation at http://qt.nokia.com/doc/4.6/platform-specific.html for platform specific building documentation

Depending on how your distribution packages ncurses you may also require libtinfo5, a separate terminfo library.

On some older versions of Ubuntu (notably 11.10) there is a packaging defect that may cause your build to blow up in SCons. It’s a missing package info file for the tinfo library. To fix this, install the file packaging/tinfo.pc in /usr/lib/pkgconfig/tinfo.pc. 13.10 fixed this.

If your kernel provides the RFC 2783 KPPS (kernel PPS) API, gpsd will use that for extra accuracy. Many Linux distributions have a package called "pps-tools" that will install KPPS support and the timepps.h header file. We recommend you do that. If your kernel is built in the normal modular way, this package installation will suffice.

For building from the source tree, or if you change the man page source, Asciidoctor is to generate nroff -man source from asciidoc markup. The following packages are used in this process:

If both are present, then AsciiDoctor is preferred.

On Gentoo systems this packages is named:

The build degrades gracefully in the absence of any of these. You should be able to tell from scons messages which extensions you will get.

Under Ubuntu and most other Debian-derived distributions, an easy way to pick up the prerequisites is: "apt-get build-dep gpsd". Note that your sources.list will need "deb-src" lines for this, not just "deb" lines.

If you are custom-building a Linux kernel for embedded deployment, you will need some subset of the following modules:

These are listed in rough order of devices covered as of 2013; the PL23203 by itself accounts for over 70% of deployed USB mice. We recommend building with pl2303, ftdi_sio, cypress_m8, and cp210x.

We’ve received a bug report that suggests the Python test framework requires legacy PTY support (CONFIG_LEGACY_PTYS) from the Linux kernel. You should make sure you’re in the 'dialout' group in order to have permission to use these devices.

Adding prefix=/usr/foo will cause scons to install to /usr/foo instead of the default /usr/local, much as --prefix=/usr/foo works with autoconf.

In addition, there are a number of other scons command-line variables that can be used to control the location of various install directories. Many of these, such as bindir — which unsurprisingly defaults to "bin" — are unlikely to be ever used. Generally, these can be set to absolute paths or relative paths. Relative paths are under prefix. See SConscript and search for "bindir" to see the list.

Some of these variables are typically used to adapt to differing layout conventions. For example, pkgsrc would use docdir=share/doc/gpsd as per-package documentation is placed in prefix/share/doc/PKGNAME, and mandir=man as man pages are in prefix/man rather than prefix/share/man.

The includedir= argument sets the location to which gpsd’s include files (gps.h, libgpsmm.h) are installed. So using prefix=/usr/foo and includedir=/usr/bar/include will install everything but includes in /usr/foo and put the includes in /usr/bar. This is highly unlikely to be desired, but given to illustrate the behavior.

The includedir=/usr/foo/include argument has no other effects; in particular it does add -I/usr/foo/include to compilation lines.

This section explains how to configure the build to find prerequisites. It can be skipped by those who find that the build succeeds.

Software that is needed to build gpsd may in general be in various locations. (While many GNU/Linux users doing a straightforward build will have all prerequisites in /usr, most other operating systems have additional software in other than /usr, and even on Linux one may wish to build a separate copy of gpsd with alternate versions of prerequisites.)

The build will invoke the compiler and linker, so that headers and libraries in the default compiler and linker search paths will be found without any additional configuration.

In addition, scons will use pkgconfig to find some prerequisites. These will be found if the pc files are in the default pkgconfig search path, and the resulting -I and -L flags added to the compile and link lines.

The gpsd scons build scripts also support passing in CPPFLAGS and LDFLAGS via environment variables, similar to how these are used with autoconf and almost all other build systems. As an example, CPPFLAGS=-I/usr/foo/include will cause -I/usr/foo/include to be added to compilation lines.

A cheat sheet for building gpsd from git source on a freshly installed Gentoo. Perform these steps, in order, as root.

The '--noreplace' option to 'emerge' prevents reinstalling packages that are already installed.

gpsd will build, install and run on macOs. Install the Xcode application from the Apple store. Then install Homebrew (https://brew.sh/) to get all the stuff you need, like git, scons, python, etc.

As a normal user, install homebrew, then install scons and asciidoctor. Installing scons pulls in python3. Brew will become root as needed, so starting asd a normal user is just security theater.

Now you need to become root. Make a place for the gpsd source to live, use git to install it there, then go there. Build gpsd with "scons", then install it with "scons install"

gpsd will build, install and run on OS X (osX). The easiest way to do so is to first install the MacPorts package. Follow their install procedure at: http://www.macports.org/install.php

Then use their port command to install scons. Optionally git if you want to access the development source. Optionally install asciidoctor to build the documentation.

Currently the osX port does not work with Qt5. To see the build failure:

If you have Qt5 installed, and want to avoid the build failure, build this way:

While running gpsd, or scons check, you may run out of shared memory segments. If so, you will see this error message:

By default OS X allows a very small number of shared segments. You can check your allowed maximum number of shared segments, then increase the maximum number, with these commands:

If you are using a USB based GPS you will likely need the Prolific PL2303 driver. You can find it here: http://www.prolific.com.tw/US/ShowProduct.aspx?p_id=229&pcid=41

Before compiling gpsd from source, you will need to update your system as root. Switching to the latest Raspbian distribution (Buster) is strongly recommended.

Multiple versions of gpsd can not co-exist on the same system. You need to ensure gpsd from a package is not on the system:

Then install the required packages:

Git-core is required to build from a git repository. pps-tools is for PPS timing.

The rest of the installation is just as for any other source based install, as already described above.

gpsd will build, install and run on FreeBSD. Due to the missing CAN bus support (linux/can.h), NMEA2000/CAN is not supported on FreeBSD.

Use their pkg command to install scons, and optionally git if you want to access the development source.

If you want to build the QT bindings, you’ll also need the qt5-network and pkgconf packages.

OpenBSD names scons differently, and uses a different Python. On OpenBSD 13.0, you need to do this to install scons and Python:

FreeBSD fails to create the python links as required by PEP394. So you need to add them yourself, as above.

gpsd will build, install and run on NetBSD.

Use their 'pkg_add' command to install pkgin. Then use pkgin to install the required tools.

gpsd will build, install and run on OpenBSD.

First, update your system. Then all you need for a basic gpsd install is scons and git. Then create the missing python link.

Yes, OpenBSD 7.0 still uses Python 2.7.

Then install the normal way.

OpenBSD 7.2 may require the linker flag -fPIC in order to completely build. Set LDFLAGS="-fPIC".

gpsd currently will build, install and run on Fedora 32, to 37. Any supported architecture should work.

Upgrade your packages, install the gcc compiler and tools. Clone the gpsd source, and then build it. Fedora recommends a reboot after using dnf.

If you wish to make an rpm of your build:

gpsd currently will build, install and run on CentOS 7.

Install the gcc compiler and tools. Install EPEL.

Note: there is no EPEL for i386.

Use the yum command to install git if you want to access the development source.

Sometimes, changes are made to code that cause the output to be different. Examples are bug fixes and changes to precision. In these cases, the regression tests must be updated. This is dangerous, and one must guard against the possibility of introducing a bug and recording that bug’s output as the desired state.

A suggested procedure is

This means your gpsd binary was constructed in a way that does not support strict IEEE 754 Floating Point operation. In this case, the regression tests ("scons check") will likely fail.

A possible workaound for the i686 (32-bit) mode build with gcc is to set the CCFLAGS to force a compliant mode. Like this: