#include <stdio.h>  #include <stdlib.h>      /**   * Create random UUID   *   * @param buf - buffer to be filled with the uuid string   */  char *random_uuid( char buf[37] )  {      const char *c = "89ab";      char *p = buf;      int n;          for( n = 0; n < 16; ++n )      {          int b = rand()%255;              switch( n )          {              case 6:                  sprintf(                      p,                      "4%x",                      b%15 );                  break;              case 8:                  sprintf(                      p,                      "%c%x",                      c[rand()%strlen( c )],                      b%15 );                  break;              default:                  sprintf(                      p,                      "%02x",                      b );                  break;          }              p += 2;              switch( n )          {              case 3:              case 5:              case 7:              case 9:                  *p++ = '-';                  break;          }      }          *p = 0;          return buf;  }