c# - Parents child threads not exiting properly -

need little regarding multithreading. doing computation in separate threads in unity , rendering result when threads completed.

below structure of code.

         thread 1     |                | thread 1.1       thread 1.2     |                | thread 1.1.2.1   thread 1.2.1.1 thread 1.1.2.2   thread 1.2.2.2 ...              ... 

every time thread 1.1 , child (thread 1.1.2.1..) exits using join() not case thread 1.2; thread 1.2.1.1.. exits without completing code block. looks join() on childthreadlist not blocking current thread in case of thread 1.2.

code simple making blocks of large list , process them in parallel. having same issue thread 1.1 , thread 1.2 exits in midway; reason sharing same variable values when on .start(). make sure not reason now.

is there mistaking or missing, please advice.

example code:

//running in thread 1; started main() private unsafe void addsurfacedata() {     float* points;     int points_length;      float* colours;     int colours_length;      system.uintptr *indices;     int indices_length;      //set references points, colours, indices, points_length, colours_length, indices_length      processtriangles(points, indices, colours, indices_length); }  private unsafe void processtriangles(float* points, system.uintptr *indices, float* colours, int indices_length) {     list<thread> threadlist = new list<thread>();      int currlength = 65535;     int initiallength = 0;      while(true)     {         if(currlength < indices_length)         {             int = initiallength;             int = currlength;              //add surfacedata             int surfaceindex = surfacedata.count-1;              //start thread initiallength currlength              thread thread = new thread(() => addtriangle(from, to, indices, points, colours, surfaceindex));             threadlist.add(thread);             thread1count++;             thread.name = "thread 1."+thread1count;             thread.start();              initiallength = currlength;             currlength += 65535;         }          else         {             int = initiallength;             int = indices_length;              //add surfacedata             surfacedata.add(new scanmanager.surfacedata(new vector3[to-from], new color[to-from], new int[to-from]));             int surfaceindex = surfacedata.count-1;              //start thread initiallength indices_length             thread thread = new thread(() => addtriangle(from, to, indices, points, colours, surfaceindex));             threadlist.add(thread);             thread1count++;             thread.name = "thread 1."+thread1count;             thread.start();              break;         }     }      foreach(thread thread in threadlist)     {        thread.join();     } }  private unsafe void addtriangle(int fromlength, int tolength, system.uintptr *indices, float* points, float* colours, int surfaceindex) {     list<thread> childthreadlist = new list<thread>();      int initiallength = fromlength;     int currlength = 21000+initiallength;     int index = surfaceindex;     int indiceslength = tolength;      while(true)     {         if(currlength < indiceslength)         {             int = initiallength;             int = currlength;              //start thread initiallength currlength              thread childthread = new thread(() => addtriangledata(from, to, indices, points, colours, index));             childthreadlist.add(childthread);             thread2count++;             childthread.name = thread.currentthread.name+".2."+thread2count;             childthread.start();              initiallength = currlength;             currlength += 21000;         }          else         {             int = initiallength;             int = indiceslength;              //start thread initiallength indices_length             thread childthread = new thread(() => addtriangledata(from, to, indices, points, colours, index));             childthreadlist.add(childthread);             thread2count++;             childthread.name = thread.currentthread.name+".2."+thread2count;             childthread.start();              break;         }     }     foreach(thread childthread in childthreadlist)    {      childthread.join();    } }  private unsafe void addtriangledata(int fromlength, int tolength, system.uintptr *indices, float* points, float* colours, int surfaceindex) {     for(int i=fromlength; i<tolength; i+=3)     {         //addtrianglevertex (i)         //addtrianglevertex (i+1)         //addtrianglevertex (i+2)     } }