Compilare: user.c: In function ‘main’: user.c:46:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:47:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:49:5: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result] read(STDIN_FILENO, buf, CHUNK); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:38:35: warning: ‘in.c’ may be used uninitialized in this function [-Wmaybe-uninitialized] visited[l][c >> 3] |= 1 << (c & 7); ~~~^~~~ user.c:44:18: note: ‘in.c’ was declared here struct point in, p; ^~ user.c:44:18: warning: ‘in.l’ may be used uninitialized in this function [-Wmaybe-uninitialized]