Compilare: main.c:6:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("O3") main.c:7:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas] #pragma GCC optimization ("unroll-loops") In file included from main.c:1:0: main.c: In function 'read': main.c:10:17: warning: implicit declaration of function 'getchar_unlocked' [-Wimplicit-function-declaration] #define getchar getchar_unlocked ^ main.c:16:24: note: in expansion of macro 'getchar' while (!isdigit(ch=getchar())); ^~~~~~~ main.c: In function 'print': main.c:11:17: warning: implicit declaration of function 'putchar_unlocked' [-Wimplicit-function-declaration] #define putchar putchar_unlocked ^ main.c:29:9: note: in expansion of macro 'putchar' putchar(a%10 + '0'); ^~~~~~~ main.c: In function 'main': main.c:65:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in", "r", stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:66:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out", "w", stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~