c - Program halts after while loop fget() -

i've been trying solve on few days , it's still doing head in. had scrappy working program, , decided clean little, something's gone wrong in process. part of program puts csv data (from file rfile4) new file (tmp41) use later:

    file *report4=fopen(rfile4,"r");     file *tmp41=fopen(tmpfile41,"w+");      if(!tmp41||!report4)      {         fprintf(stderr, "failure - 'report' input file not found\n");         exit(exit_failure);     }      const char comma[2]=",";     int nreports=0;      while(fgets(line,size,report4)!=null)     {         char linestore[size];         char mcodecheck[size];          strncpy(linestore,line,size);         char *tkndmp=linestore;          int count1=0;          while((tkndmp=strtok(tkndmp,comma))!=null)         {                    count1++;              if(count1==4)             {                 sscanf(tkndmp,"%s",mcodecheck);                  if(strcmp(mcode,mcodecheck)==0)                 {                    nreports++;                    fputs(line,tmp41);                 }             }              tkndmp=null;         }      }      printf("success");     fclose(report4);     rewind(tmp41); 

the 'mcode' string found earlier, , i've confirmed that's right. file locations correct. data correctly input new file, whole program eternally pauses after loop, , never see 'success' printed.

any ideas? had working previously, main changes cleaning strtok business, suspect may have made error that, or pointers. if remove code within loop, exits fine.

new line required print line string.