casting char[][] to char** causes segfault?

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A char[ROWS][COLS+1] cannot be cast into a char**. The input argument of print_map should be

void print_map(char map[][COLS+1])

or

void print_map(char (*map)[COLS+1])

The difference being that a char** means to point to something that can be dereferenced like this:

   (char**)map
       |
       v
  +--------+--------+------+--------+-- ...
  | 0x1200 | 0x1238 | NULL | 0x1200 |
  +----|---+----|---+--|---+----|---+-- ...
       v        |      =        |
    +-------+   |               |
    | "foo" | <-----------------'
    +-------+   |
                v
             +---------------+
             | "hello world" |
             +---------------+

While a char(*)[n] is a points to a continuous memory region like this

   (char(*)[5])map
       |
       v
  +-----------+---------+---------+-------------+-- ...
  | "foo\0\0" | "hello" | " worl" | "d\0\0\0\0" |
  +-----------+---------+---------+-------------+-- ...

If you treat a (char(*)[5]) as a (char**) you get garbage:

   (char**)map
       |
       v
  +-----------+---------+---------+-------------+-- ...
  | "foo\0\0" | "hello" | " worl" | "d\0\0\0\0" |
  +-----------+---------+---------+-------------+-- ...
      force cast (char[5]) into (char*):
  +----------+------------+------------+------------+-- ...
  | 0x6f6f66 | 0x6c686500 | 0x77206f6c | 0x646c726f |
  +----|-----+---------|--+------|-----+------|-----+-- ...
       v               |         |            |
    +---------------+  |         |            v
    | "hsd®yœâñ~22" |  |         |       launch a missile
    +---------------+  |         |
                       v         v
               none of your process memory
                        SEGFAULT

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