linux_aio.zip_LINUX下开启AIO_aio glibc_aio 两种方式_linux aio_linux_aio

/*lab2.c *author: zxh *system propraming lab2 */ #include <stdio.h> #include <signal.h> #include <aio.h> #include <string.h> #include <malloc.h> #include <error.h> #define BUF_SIZE 4096 int aio_completion_handler(int, siginfo_t*, void *); int get_file_size(const char *); int finished = 0; int filesize = -1; int timesToRead = -1; int timesRead = 0; struct aiocb my_aiocb; int main(void) { printf("\nWelcome to my simple aio!\n"); int fd,ret; struct sigaction sig_act; printf("Buffer size is :%d\n", BUF_SIZE); /* Get the file size */ filesize = get_file_size("./testfile"); printf("The file size is %d\n", filesize); timesToRead = filesize / BUF_SIZE; printf("Times to read: %d\n", timesToRead + 1); /* Open the file, readonly */ if((fd = open("./testfile", O_RDONLY)) < 0){ perror("open error!\n"); } /* Set up the signal handler */ sigemptyset(&sig_act.sa_mask); sig_act.sa_flags = SA_SIGINFO; sig_act.sa_sigaction = aio_completion_handler; /* Set up the AIO request */ bzero( (char *)&my_aiocb, sizeof(struct aiocb) ); my_aiocb.aio_fildes = fd; my_aiocb.aio_buf = malloc(BUF_SIZE+1); my_aiocb.aio_nbytes = BUF_SIZE; my_aiocb.aio_offset = 0; /* Link the AIO request with the Signal Handler */ my_aiocb.aio_sigevent.sigev_notify = SIGEV_SIGNAL; my_aiocb.aio_sigevent.sigev_signo = SIGIO; my_aiocb.aio_sigevent.sigev_value.sival_ptr = &my_aiocb; /* Map the Signal to the Signal Handler */ ret = sigaction( SIGIO, &sig_act, NULL ); if(ret < 0) perror("sigaction:\n"); /* Call asynchronous I/O functions */ ret = aio_read(&my_aiocb); if(ret < 0) perror("aio_read request:\n"); else printf("Start asynchronous I/O reading...\n"); /* Continue processing, in this case just sleep */ while(!finished){ printf("sleeping...\n"); sleep(1); } /* Asynchronous I/O finished */ if((ret = aio_return (&my_aiocb)) > 0) { printf("Asynchronous I/O OK, file size: %d\n", timesToRead * BUF_SIZE + ret); close(fd); } printf("Time to say goodbye!\n\n"); } /* aio_completion_handler * deliver the SIGIO signal * params: signo info context * ret; */ int aio_completion_handler( int signo, siginfo_t *info, void *context ) { struct aiocb * req; int ret; /* Ensure it's our signal */ if (info->si_signo == SIGIO) { req = (struct aiocb*)info->si_value.sival_ptr; if(aio_error(req) == 0){ timesRead ++; printf("read %d times\n", timesRead); } if(timesRead > timesToRead){ finished = 1; return timesRead * BUF_SIZE; } else{ my_aiocb.aio_offset += BUF_SIZE; /* Call asynchronous I/O functions */ ret = aio_read(&my_aiocb); if(ret < 0) perror("aio_read request:\n"); } } return ret; } /* get_file_size * get the size of a file * params：file path, const char * ret： file size, int * error：-1 */ int get_file_size(const char *path) { int filesize = -1; struct stat statbuff; if(stat(path, &statbuff) < 0){ perror("get file size error!\n"); return filesize; }else{ filesize = statbuff.st_size; } return filesize; }