首先，貼一下非同步io中用的的一些結構體，因為平常很少用，整理起來方便查看。
aio.h中的struct aiocb
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;
};
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siginfo.h中的struct sigevent和union sigval
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
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typedef union sigval
{
int sival_int;
void *sival_ptr;
} sigval_t;
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例子1：
#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;
}
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運行結果：
注意：要加相應的庫，-lrt
$ ./test
0
1
h2
ell3
o
read=hello
4
^c
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例子2：
#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;
}
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運行結果同上。
