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FAQ for Pd

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Frequently Asked Questions regarding Pd (now with answers) If you have something to contribute to this page, log into and you will have edit access.

Problems and Fixes

Gem is crashing X11 in GNU/Linux when using the fglrx graphics driver

If you're using the fglrx driver & X11 is crashing on opening GEM patches, you need to set the environmental variable of GEM_SINGLE_CONTEXT=1 by adding the following to your ~/.bashrc or /etc/profile:


if you are using a different shell (e.g. "tcsh") the procedure might be slightly different.

On GNU/Linux, the fonts are strange and/or too big or small

Watch out for old versions of Tcl/Tk (8.4 or older)

Tcl/Tk 8.4 and earlier tried to a lot of guessing about the fonts, and often got things wrong. Use Tcl/Tk 8.5 or newer with Pd and the fonts will work much better.

If you are running a Debian-based GNU/Linux (Debian, Ubuntu, Mint, Knoppix, etc), try making sure that your wish shell is 8.5 or newer:

sudo apt-get install tk8.5

sudo update-alternatives --config wish

Rebuild the Font Database

This is because Pd cannot find the correct font. First, you need to make sure that you have the right font-handling packages installed, ttf-dejavu and x-ttcidfont-conf. You can check those in Synaptic

If they were already installed, then try reinstalling them, using this command in the Terminal:

sudo apt-get install --reinstall x-ttcidfont-conf ttf-dejavu

Specify a Font

One can also try to use the -font-face startup option. You can search for fonts with the "fc-match" command like:

$ fc-match mono

The best known fonts for Pd on GNU/Linux are "Courier 10 Pitch", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Droid Sans Mono", and "Andale Mono".

$ pd -font-face "Andale Mono"

How do I report a bug?

All bugs should be reported to the pure-data bug tracker on SourceForge. When making a report, you should first search through the existing reports to make sure that it hasn't been reported already. If there is an existing report, please add your information to that report.

Here are the various ways to find the bug tracker:

Here is some of the information that should include in your report:

  • exact operating system and version (e.g. Debian/stable, Ubuntu Hardy, Windows XP SP2, Mac OS X 10.4.11)
  • exact version of Pd where the bug is occuring (e.g. Pd-vanilla 0.41-4, Pd-extended 0.40.3-extended-20080703)
  • other versions of Pd where the bug was tested
  • other operating systems where the bug was tested
  • if there was a crash, include the crash log

When I upgraded to Pd-extended 0.40.3, it stopped loading all of the libraries.

If you upgraded to Pd-extended 0.40.3, and you get a lot of messages like this in your Pd window: :

  cyclone: can't load library
  zexy: can't load library
  cxc: can't load library
  ext13: can't load library

Then, you need to update your preferences. The default preferences are now embedded in the app, so you can just delete your own preferences file and Pd-extended will use the embedded preferences. You can find out where the preference file is on your Operating System by checking the pdsettings FAQ entry

If you want to keep your preferences file, then you need to add libdir as the first library loaded.

How do I fix this error: "Library not loaded: /usr/X11R6/lib/libX11.6.dylib"?

Library not loaded: /usr/X11R6/lib/libX11.6.dylib

If you get this error in the Pd window when starting Gem, PDP, or Pd-extended, then that means that you are missing X11. (This happens almost exclusively on Mac OS X since GNU/Linux almost always includes it by default.)

To fix this, install X11: How do I install Pd on MacOS X?

Pd does not launch.

On OS X the icon in bouncing in the Dock but then stops and Pure Data is not starting.

If Pure Data is not launching on your computer, then check if your /private/etc/hosts file is configured correctly.
You may get the message ERROR: failed to allocate port, exiting! in the console.

The default under OS X looks like this:

# Host Database
# localhost is used to configure the loopback interface
# when the system is booting. Do not change this entry.
## localhost broadcasthost
::1 localhost
fe80::1%lo0 localhost

if localhost is missing in yours then Pd can't start. It will hang and quit on startup.

Read about the hosts file on wikipedia

How do I get an acceptable performance and latency on the MS Windows platform?

I've Installed Pure Data (or Pd-extended) on Windows and I have to set the buffer (delay) to more than 100ms to avoid audio drop outs (crackling). What can I do to achieve a proper latency in Pd on Microsoft Windows?

Make sure your Windows system is set up for Audio. Make sure the overall system performance is OK, install updated ASIO drivers for your soundcard or the "ASIO4All Drivers": when no ASIO is available from the manufacturer. There is also an "ASIO driver for WDM kernel-streaming compliant soundcards":

Read Native Instrument's "Windows 7 Tuning Tips for Audio Processing":

Also read RME's "Tuning Tips for Low Latency Operation": (slightly older, possibly outdated)

USB and persitency

If you have the problem that you can only plug in your external sound card to one specific USB port you might want to make the COM port assignment of the system permanent to this device. Here is How: goto control panel -> device manager -> com ports -> properties -> port settings -> advanced -> comport number there you can permanently set the comport number for that device.

Why doesn't audio work when I start Pd in -nogui mode?

When I start Pd from the commandline without the GUI in -nogui mode, it can't connect to the soundcard and no dsp seems to happen?

Currently, there is a bug in Pd where starting in -nogui mode causes patches to be run before it connects to a sound card. When running the graphical user interface (GUI), there is a delay as the GUI is being setup before patches are run and this is enough time for the sound to be connected. Basically, if you are turning on dsp with a loadbang like this:
[; pd dsp 1(
Pd tries to start dsp, but in -nogui mode, it hasn't yet connected to the sound card and you'll get an error similar to this:
snd_pcm_open (input): Device or resource busy 
snd_pcm_open (output): Device or resource busy
If so, you can add a delay before starting the dsp:
[delay 100]
[; pd dsp 1(
This should be enough time to mimic the delay taken when the GUI starts and the sound card can be setup before dsp is started.

Help! Pd crashes on startup on Mac OSX 10.7+

Is Pd crashing on startup and you're using Mac OSX 10.7 or greater (Lion, Mountain Lion, Mavericks, etc)? This might be happening since newer versions of OSX save the window state when apps are closed and reopen them for you. This can be bad for Pd if there is a clash over resources (sockets, etc) when trying to open patches too quickly or simultaneously.

Luckily, there is a way to manually tell the operating system to not save window states and that's by either setting a defaults option or by simply locking the folder where this information is kept. This way it always opens Pd with an empty state.

A Clean Slate

First, make sure to remove the existing state, otherwise it will keep opening with whatever windows it last saved. You can hold Option when quitting (aka Cmd+Opt+Q) Pd to bypass the OSX save state mechanism and delete any current states.

Another option is to use the Terminal:

rm -rf ~/Library/Saved\ Application\ State/org.puredata.*

If you had startup crashes, this should at least get Pd back but it dosen't disable state saving ...

Option1: Setting Defaults Option

The easiest method to disable the state saving mechanism for Pd is by setting a user defaults option which tells OS X *not* to save Pd's window state by default when quitting:

defaults write org.puredata NSQuitAlwaysKeepsWindows -bool false

Now restart Pd. Upon quitting, Pd will not remove any window states that are set. Also, if you *do* want to save the window states, hold the Option/Alt key while quitting via the File menu or the Cmd+Q key binding.

Option 2: Locking the State Folder

You can disable the state saving mechanism for Pd by locking the state folder for Pd-Extended using the Get Info dialog (CMD+I):

~/Library/Saved\ Application\ State/org.puredata.*

"~/" is your user home directory.

There may be more then one folder named "org.puredata..." as (at the time of writing), Pd-vanilla and Pd-extended use slightly different identifiers. Anyway, if you're clearing one, you'd probably want to clear both.

As before, you can also use the Terminal:

chflags -v uchange ~/Library/Saved\ Application\ State/org.puredata.*

The "uchange" flag locks the folder.


by Frank Barknecht last modified 2009-05-18 09:44 PM

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