Eroare de compilare: user.c: In function ‘main’: user.c:25:1: warning: implicit declaration of function ‘ftruncate’ [-Wimplicit-function-declaration] if(ftruncate(shm_fd, shm_size) ==-1) ^ user.c:16:6: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.c:53:7: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a); ^ user.c:25:13: warning: ‘shm_fd’ is used uninitialized in this function [-Wuninitialized] if(ftruncate(shm_fd, shm_size) ==-1) ^ /tmp/cc3wyLJS.o: In function `main': user.c:(.text.startup+0x9f): undefined reference to `shm_open' user.c:(.text.startup+0x1c5): undefined reference to `shm_unlink' collect2: error: ld returned 1 exit status