# FMOD CORE API | file thread crash on iOS only **URL:** \ **Category:** FMOD Engine\ **Tags:** ios, cpp\ **Created:** [December 1, 2020, 7:47am UTC](https://qa.fmod.com/t/fmod-core-api-file-thread-crash-on-ios-only/16498 "2020-12-01T07:47:55Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Rafaelb149](https://avatars.discourse-cdn.com/v4/letter/r/c67d28/32.png) [@Rafaelb149](https://qa.fmod.com/u/Rafaelb149)\ **Post date:** [December 1, 2020, 7:47am UTC](https://qa.fmod.com/t/fmod-core-api-file-thread-crash-on-ios-only/16498/1 "2020-12-01T07:47:56Z")
Hi We developed a cross-platform c++ mobile app using FMOD (2.01.06), both platforms use the same base code. On iOS clients only, we observe crashes of FMOD file thread via crashlytics. The following stack trace provided by crashlytics: FMOD file thread 0 libsystem\_kernel.dylib \_\_semwait\_signal + 8 1 libsystem\_c.dylib nanosleep + 220 2 libsystem\_c.dylib usleep + 64 3 MyApp FMOD\_OS\_Time\_Sleep + 20 4 MyApp FMOD:: Thread::callback(void\*) + 164 5 MyApp FMOD\_OS\_Thread\_Callback(void\*) + 76 6 libsystem\_pthread.dylib \_pthread\_start + 156 7 libsystem\_pthread.dylib thread\_start + 8 Waiting for your insights 🙂 ---
**Author:** ![mathew](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/mathew/32/431_2.png) [@mathew](https://qa.fmod.com/u/mathew)\ **Post date:** [December 3, 2020, 3:07am UTC](https://qa.fmod.com/t/fmod-core-api-file-thread-crash-on-ios-only/16498/2 "2020-12-03T03:07:04Z")
That callstack doesn’t look like it has crashed to me, that is our file thread calling sleep. Do you have any additional details about the crash or know how to reproduce it? ---
**Author:** ![Rafaelb149](https://avatars.discourse-cdn.com/v4/letter/r/c67d28/32.png) [@Rafaelb149](https://qa.fmod.com/u/Rafaelb149)\ **Post date:** [December 3, 2020, 6:03am UTC](https://qa.fmod.com/t/fmod-core-api-file-thread-crash-on-ios-only/16498/3 "2020-12-03T06:03:45Z")
You’re right, but this is all I got from crashlytics at this point. they consider it as a crash. I don’t see any thread in the thread stack that marked as crashed. I will try to investigate a little bit more and come with my insights. ---
**Author:** ![mathew](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/mathew/32/431_2.png) [@mathew](https://qa.fmod.com/u/mathew)\ **Post date:** [December 3, 2020, 9:25pm UTC](https://qa.fmod.com/t/fmod-core-api-file-thread-crash-on-ios-only/16498/4 "2020-12-03T21:25:48Z")
Are there any other threads with callstacks in FMOD?