linux下异步IO的简单例子【转】

struct aiocb
{
int aio_fildes;        /* File desriptor. */
int aio_lio_opcode;        /* Operation to be performed. */
int aio_reqprio;        /* Request priority offset. */
volatile void *aio_buf;    /* Location of buffer. */
size_t aio_nbytes;        /* Length of transfer. */
struct sigevent aio_sigevent;    /* Signal number and value. */

/* Internal members. */
struct aiocb *__next_prio;
int __abs_prio;
int __policy;
int __error_code;
__ssize_t __return_value;
};

typedef struct sigevent
{
sigval_t sigev_value;
int sigev_signo;
int sigev_notify;

union
{
int _pad[__SIGEV_PAD_SIZE];

/* When SIGEV_SIGNAL and SIGEV_THREAD_ID set, LWP ID of the
thread to receive the signal. */
__pid_t _tid;

struct
{
void (*_function) (sigval_t);    /* Function to start. */
void *_attribute;            /* Really pthread_attr_t. */
} _sigev_thread;
} _sigev_un;
} sigevent_t;

/* POSIX names to access some of the members. */
# define sigev_notify_function _sigev_un._sigev_thread._function
# define sigev_notify_attributes _sigev_un._sigev_thread._attribute

typedef union sigval
{
int sival_int;
void *sival_ptr;
} sigval_t;

#include <aio.h>#include <fcntl.h>#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <signal.h>void async_read(int s, siginfo_t * info, void * context){struct aiocb *ptr =(struct aiocb *)info->si_value.sival_ptr;printf("read=%s", (char *)ptr->aio_buf);}int main(void){struct aiocb cb;char sbuf[100];int ret;struct sigaction act;sigemptyset(&act.sa_mask);act.sa_flags = SA_RESTART | SA_SIGINFO;act.sa_sigaction = async_read;sigaction(SIGUSR1, &act, NULL);bzero(&cb, sizeof(cb));cb.aio_fildes = 0;cb.aio_buf = sbuf;cb.aio_nbytes = 100;cb.aio_offset = 0;cb.aio_sigevent.sigev_value.sival_ptr = &cb;cb.aio_sigevent.sigev_notify = SIGEV_SIGNAL;cb.aio_sigevent.sigev_signo = SIGUSR1;ret = aio_read(&cb);if (ret == -1) {perror("aio_read");exit(1);}int i = 0;while (1) {printf("%d\n",i++);sleep(3);}return 0;}

$ ./test01h2ell3oread=hello4^C

#include <aio.h>#include <fcntl.h>#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>void async_read(sigval_t val){struct aiocb *ptr =(struct aiocb *)val.sival_ptr;printf("read=%s", (char *)ptr->aio_buf);}int main(void){struct aiocb cb;char sbuf[100];int ret;bzero(&cb, sizeof(cb));cb.aio_fildes = 0;cb.aio_buf = sbuf;cb.aio_nbytes = 100;cb.aio_offset = 0;cb.aio_sigevent.sigev_value.sival_ptr = &cb;cb.aio_sigevent.sigev_notify = SIGEV_THREAD;cb.aio_sigevent.sigev_notify_function =async_read;cb.aio_sigevent.sigev_notify_attributes = NULL;ret = aio_read(&cb);if (ret == -1) {perror("aio_read");exit(1);}int i = 0;while (1) {printf("%d\n",i++);sleep(1);}return 0;}