# DSP::GetUserData() question... **URL:** \ **Category:** FMOD Studio\ **Created:** [July 8, 2016, 7:57pm UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578 "2016-07-08T19:57:41Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![rory](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rory](https://qa.fmod.com/u/rory)\ **Post date:** [July 8, 2016, 7:57pm UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/1 "2016-07-08T19:57:41Z")
Following some advice I received in a previous post I’ve taken a look at the GetUserData() method. I tried adding a call to that function in the fmod\_noise plugin example. I had to add fmodL64\_vc.lib as an additional library dependency, without it I kept getting “unresolved externals” errors regarding DSP::GetUserData(). After building and running, FMOD Studio no longer sees the noise plugin. I noticed that none of the other plugin projects link to this lib, so I’m guessing that is not how I should have resolved that build error? Any ideas? ---
**Author:** ![brett](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/brett/32/261_2.png) [@brett](https://qa.fmod.com/u/brett)\ **Post date:** [July 10, 2016, 2:25am UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/2 "2016-07-10T02:25:34Z")
If you want to store your own data so you can access it from any callback, then you use FMOD\_DSP\_STATE::plugindata. This is what the noise plugin example does. DSP::setUserData is data set by the user, not for use within the plugin. You can use FMOD\_DSP\_STATE::instance to get this sort of data if the DSP is statically created and linked within your executable, because the code is there. If you are in a DLL environment, then you need the code to be linked in, but if the dll tries to load fmodL64.dll and fails then it will most likely fail to load as a plugin. Its generally not a great idea to try and access FMOD through a dll interface, are you just after the ability to store your own data (ie plugindata) or you really want what the user set from the application? That’s not a typical use case. The setParameter interface is used to pass data from the user to the plugin, not setUserData. ---
**Author:** ![rory](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rory](https://qa.fmod.com/u/rory)\ **Post date:** [July 10, 2016, 7:16am UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/3 "2016-07-10T07:16:25Z")
Thanks for your reply. pluginData will not work for me in this case. Let me explain. I’m dynamically creating a list of plugins by populating a vector of FMOD\_DSP\_DESCRIPTION structs in my FMODGetPluginDescriptionList() method. At this point my interface knows nothing about my plugin data. What I would like to do is set a unique string at this stage, in each of my descriptors, that I can retrieve in any of their callbacks. There are hacky ways I can do it. For example I can create a global vector of strings that I populate in FMODGetPluginDescriptionList(). I could then set a unique index as the descriptors version number which I can then access in my callback to ensure I find the right string in the vector. But it’s rather crude. Any other ideas? Btw, this question was a follow up to this one: [http://www.fmod.org/questions/question/question-regarding-multiple-plugins-in-one-dll/](http://www.fmod.org/questions/question/question-regarding-multiple-plugins-in-one-dll/) ---
**Author:** ![brett](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/brett/32/261_2.png) [@brett](https://qa.fmod.com/u/brett)\ **Post date:** [July 11, 2016, 1:08am UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/4 "2016-07-11T01:08:45Z")
> [@](#): > > Thanks for your reply. pluginData will not work for me in this case. Let me explain. I’m dynamically creating a list of plugins by populating a vector of FMOD\_DSP\_DESCRIPTION structs in my FMODGetPluginDescriptionList() method. At this point my interface knows nothing about my plugin data. What I would like to do is set a unique string at this stage, in each of my descriptors, that I can retrieve in any of their callbacks. > > There are hacky ways I can do it. For example I can create a global vector of strings that I populate in FMODGetPluginDescriptionList(). I could then set a unique index as the descriptors version number which I can then access in my callback to ensure I find the right string in the vector. But it’s rather crude. Any other ideas? > > Btw, this question was a follow up to this one: > [question regarding multiple plugins in one dll.. - FMOD Studio - FMOD Forums](http://www.fmod.org/questions/question/question-regarding-multiple-plugins-in-one-dll/) If you want to follow that advice you’d have to use a 2nd copy of FMOD that lives in the same directory as your plugin, as the failure you experienced is probably a failure to load the fmod dll at plugin load time, that linking the fmodL64\_vc.lib is causing. ---
**Author:** ![rory](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rory](https://qa.fmod.com/u/rory)\ **Post date:** [July 11, 2016, 8:39am UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/5 "2016-07-11T08:39:54Z")
Thanks Brett. I tried this out. I copied all the fmod dlls I could to my plugin dir but it’s still not seen by fmod studio. I tried some other DSP methods, they all result in the same problem. I see none of the plugin examples use them either. Could any of you guys confirm this is actually possible by modifying the fmod\_noise example. For example, even GetInfo causes my plugin to become invalid: ``` char name[1024]; FMOD_DSP *fmod_dsp = (FMOD_DSP *)dsp_state->instance; FMOD_DSP_GetInfo(fmod_dsp, name, 0, 0, 0, 0); ``` What’s more is my proposed hack won’t work either because I can’t access any FMOD descriptors in my callback functions. ---
**Author:** ![brett](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/brett/32/261_2.png) [@brett](https://qa.fmod.com/u/brett)\ **Post date:** [July 12, 2016, 2:02am UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/6 "2016-07-12T02:02:51Z")
It does work, but you have to remember to check the logging console in studio (under window menu) if there’s an error. Typically using a 64bit version of FMOD studio and building a 32bit plugin would be the first problem. Next linking to fmod logging version import lib, and using the release dll would mean it would fail as well. To be sure, I copy fmod64\_vc.lib and fmod64.dll into the plugins folder. Next I link my plugin to the .lib in that folder. Next I copy the linked dll into the same plugin folder. As long as they’re both 64bit it will load, and getUserData or getInfo works without a problem. I used it in the create and process callback. ---
**Author:** ![rory](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@rory](https://qa.fmod.com/u/rory)\ **Post date:** [July 12, 2016, 3:40pm UTC](https://qa.fmod.com/t/dsp-getuserdata-question/12578/7 "2016-07-12T15:40:18Z")
Thanks Brett. It turns out that trying to run my plugin from its build folder doesn’t work for some reason. But, if I throw it in the fmod plugins dir all works as expected. Clearly there was a library conflict somewhere. THanks again, that’s another hurdle out of the way!