转自：
首先，贴一下异步IO中用的的一些结构体，因为平常很少用，整理起来方便查看。
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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运行结果： 注意：要加相应的库，-lrt
$ ./gcc -o test aio_signal.c -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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运行结果同上。
本文转自张昺华-sky博客园博客，原文链接：http://www.cnblogs.com/sky-heaven/p/5847456.html，如需转载请自行联系原作者