Void * return type function is not able to access class members

I am facing problem void * return type function is not able to access class members if I make that variable as global I am able to access and if it is declared inside class then runtime it is giving me segmentation fault: In The both Condition I am sharing the code below:

Condition 1: in this apple is declared inside class so when i am trying to access apple in therad_alsa_playback function it is giving me segmentation fault

#include <pthread.h>
#include<stdio.h>
#include<unistd.h>
class alsaAudio{
private:
  int apple=1202;
  int audio_complete=1;
  pthread_t playback_thread;
public:

void *thread_alsa_playback(void *InputArgs){
        printf("printing_apple%d\n",apple);
}

int alsa_playback(){
    printf("here\n");
    if(audio_complete==0 ){
        pthread_join(playback_thread, NULL);
        audio_complete=1;
    }
    if(audio_complete==1 ){
        audio_complete=2;
        typedef void * (*THREADFUNCPTR)(void *);
        pthread_create(&playback_thread, NULL,(THREADFUNCPTR)&alsaAudio::thread_alsa_playback,NULL);
        printf("created\n");
    }
    return 0;
}



};

int main(int argc, char **argv) {
    alsaAudio voice;
    voice.alsa_playback();  
    usleep(20);
    return 0;
}

Condition 2: Here apple is global so i am able to access in thread_alsa_playback function without any error.

#include <pthread.h>
#include<stdio.h>
#include<unistd.h>
int apple=1202;
class alsaAudio{
 private:
    int audio_complete=1;
pthread_t playback_thread;
public:

void *thread_alsa_playback(void *InputArgs){
        printf("printing_apple%d\n",apple);
}

int alsa_playback(){
    printf("here\n");
    if(audio_complete==0 ){
        pthread_join(playback_thread, NULL);
        audio_complete=1;
    }
    if(audio_complete==1 ){
        audio_complete=2;
        typedef void * (*THREADFUNCPTR)(void *);
        pthread_create(&playback_thread, NULL,(THREADFUNCPTR)&alsaAudio::thread_alsa_playback,NULL);
        printf("created\n");
    }
    return 0;
}



};

int main(int argc, char **argv) {
    alsaAudio voice;
    voice.alsa_playback();  
    usleep(20);
    return 0;
}

In condition 2 there is nothing to shocked but why in condition 1 it is crashing.

I tried on internet but i didnt got any answer . If someone can help Thanks in advance.