Compilare: user.c: In function ‘PrimeNumbersSieve5’: user.c:8:1: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] char list[2000005]; memset(list, 0, 2000005); ^ user.c:8:21: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] char list[2000005]; memset(list, 0, 2000005); ^ user.c:22:1: warning: return makes integer from pointer without a cast [enabled by default] return primes; ^ user.c: In function ‘main’: user.c:35:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &T); ^ user.c:39:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &N); ^ user.c:40:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &K); ^