c - Stat errors in pthread (S_ISDIR not working) -

i attempting write program finds size of directory tree size of subdirectories within creating thread each new subdirectory , using thread find size of subdirectory. it's pretty simple program, it's hard debug. having ton of issues s_isdir not working intended (regular files passing if statement , program trying change dir regular files). below code have problem. have each parent directory wait subdirectories finish, don't want each subdirectory wait next one.

#define namesize 256 #define num_threads 100 #define max_path_length 500  int totalsum = 0; pthread_mutex_t sum_mutex ; pthread_mutex_t thread_mutex ;  void *findsize(void *p) {     int levelsum = 0, numberthreads = 0, = 0;     dir *dir ;     struct dirent *entry ;     struct stat entry_stat ;     char cwd[2049] ;     char threads[num_threads] ;     char paths[num_threads][max_path_length];      char *path = (char*)p ;      // change directory passed in     if(chdir (p) == -1)     {         perror("chdir");         exit(1);     }      // current working directory     if(!getcwd (cwd, 2049))     {         perror("getcwd") ;         return;     }      // open directory entries within     dir = opendir(".") ;     if(!dir)     {         perror("cannot read directory");         return;     }      while((entry = readdir(dir)))     {         // call stat on current entry in directory         if(stat (entry->d_name, &entry_stat) == -1)         {             perror("stat error");         }          // skip . , .. directories         if(strcmp (entry->d_name, ".") == 0)             continue;         if(strcmp (entry->d_name, "..") == 0)             continue;          // check if current entry directory         if(s_isdir (entry_stat.st_mode))         {             pthread_mutex_lock(&thread_mutex) ;             strcpy(paths[numberthreads], cwd) ;             strcat(paths[numberthreads], "/") ;             strcat(paths[numberthreads], entry->d_name) ;              pthread_t temp ;              // create new thread in threads array             if (pthread_create(&temp, null, findsize, (void *)paths[numberthreads]))             {                 fprintf("failed create thread directory %s\n ", paths[numberthreads]) ;                 exit(1) ;             }              threads[numberthreads] = temp;              // increment number of threads created on level of directory tree              numberthreads++ ;             pthread_mutex_unlock(&thread_mutex) ;          }           if(s_isreg(entry_stat.st_mode))         {             pthread_mutex_lock(&sum_mutex) ;             int filesize = entry_stat.st_size ;             levelsum += filesize ;             totalsum += filesize ;             pthread_mutex_unlock(&sum_mutex) ;         }     }      void *status ;      for(i = 0; < numberthreads; i++)     {         pthread_join(threads[i], null) ;     }  } 

in main, pthread_create function findsize , path user passes in. lots of stat errors, can't figure how fix them..

the current directory not thread-local; it's property of process. you're going end doing nonsense if each thread tries chdir. either need construct full pathnames based on results readdir without using chdir, or use "*at" interfaces (openat, fstatat, etc.) open file relative directory file descriptor.