[SOLVED] Function calling itself seg faults

errigour · 08-01-2014, 03:59 PM

I am stuck with this function that loops to itself and I keep getting a seg fault at the line of the function calling itself.
This is a nested function instide another function and it uses a
local variable. Is there any way to do this ill mark the function call with exclamation marks.

Code:

bool loop_parse_room (short int x, short int y, room_rnum parse_room)
{
     bool cont = FALSE;

     short int dir;

     if ( parse_room != 0x00 )
     {
          for ( dir = 0; dir < NUM_DIR; dir++ )
          {
               if ( dir == UP || dir == DOWN || dir == INDIR || dir == OUTDIR )
                    continue;

               if ( world[parse_room].dir_option[dir] != NULL )
               {
                         if ( dir == NORTH     )  {y--;     }
                    else if ( dir == EAST      )  {x++;     }
                    else if ( dir == SOUTH     )  {y++;     }
                    else if ( dir == WEST      )  {x--;     }
                    else if ( dir == NORTHWEST )  {x--; y--;}
                    else if ( dir == NORTHEAST )  {y--; x++;}
                    else if ( dir == SOUTHEAST )  {y++; x++;}
                    else if ( dir == SOUTHWEST )  {x--; y++;}

                    if ( x >= ch->map_width ) { x--; cont = TRUE; }
                    if ( x < 0 ) { x++; cont = TRUE; }
                    if ( y >= ch->map_height ) { y--; cont = TRUE; }
                    if ( y < 0 ) { y++; cont = TRUE; }

                    if ( cont == TRUE ) { cont = FALSE; continue; }

                    map[y][x] = world[parse_room].dir_option[dir]->to_room;
                    !!!!!!!!!loop_parse_room(x, y, world[parse_room].dir_option[dir]->to_room);
               }

               // world[world[IN_ROOM(ch)].dir_option[dir]->to_room].dir_option[dir]
          }

          return TRUE;
     }
     else
          return FALSE;
}

linosaurusroot · 08-01-2014, 05:24 PM

Are you exceeding the available stack size? Can you show a backtrace of a core dump?

NevemTeve · 08-01-2014, 09:53 PM

What this function should do? (Other than infinite recursion.)

errigour · 08-03-2014, 03:55 PM

I wouldn't call it infinit it should return after all the rooms in a square have been checked
for exits. It should start from the center and check every room with a maximum size
height of five and a width of nine. Errors below I don't think it's a stack overflow.

Code:

==7018== Stack overflow in thread 1: can't grow stack to 0xbe2c6ffc
==7018== 
==7018== Process terminating with default action of signal 11 (SIGSEGV)
==7018==  Access not within mapped region at address 0xBE2C6FFC
==7018==    at 0x804D283: loop_parse_room.6925 (act.informative.c:3391)
==7018==  If you believe this happened as a result of a stack
==7018==  overflow in your program's main thread (unlikely but
==7018==  possible), you can try to increase the size of the
==7018==  main thread stack using the --main-stacksize= flag.
==7018==  The main thread stack size used in this run was 8388608.
==7018== Stack overflow in thread 1: can't grow stack to 0xbe2c6fdc
==7018== 
==7018== Process terminating with default action of signal 11 (SIGSEGV)
==7018==  Access not within mapped region at address 0xBE2C6FDC
==7018==    at 0x4022510: _vgnU_freeres (in /usr/lib/valgrind/vgpreload_core-x86-linux.so)
==7018==  If you believe this happened as a result of a stack
==7018==  overflow in your program's main thread (unlikely but
==7018==  possible), you can try to increase the size of the
==7018==  main thread stack using the --main-stacksize= flag.
==7018==  The main thread stack size used in this run was 8388608.
==7018== 
==7018== HEAP SUMMARY:
==7018==     in use at exit: 7,483,816 bytes in 33,201 blocks
==7018==   total heap usage: 34,129 allocs, 928 frees, 8,439,100 bytes allocated
==7018== 
==7018== LEAK SUMMARY:
==7018==    definitely lost: 40 bytes in 1 blocks
==7018==    indirectly lost: 64 bytes in 4 blocks
==7018==      possibly lost: 0 bytes in 0 blocks
==7018==    still reachable: 7,483,712 bytes in 33,196 blocks
==7018==         suppressed: 0 bytes in 0 blocks
==7018== Rerun with --leak-check=full to see details of leaked memory
==7018== 
==7018== For counts of detected and suppressed errors, rerun with: -v
==7018== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Segmentation fault

ntubski · 08-03-2014, 04:38 PM

Quote:

Originally Posted by errigour

I wouldn't call it infinit it should return after all the rooms in a square have been checked
for exits.

If you have 2 adjacent rooms, room1 will have an exit to room2, and room2 will have an exit to room1. What will prevent your function from cycling between room1 and room2 endlessly?

PS get rid of the variable cont, instead of cont = TRUE; just use continue;

errigour · 08-04-2014, 07:55 AM

Thanks for the help ntubski your right it will cycle endlessly I need another if statement.

Also I need the other if statements to cycle threw that's why there is a continue. after the if statements.