关于异步IO使用的一个例子

#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <libaio.h>

int main()
{
        io_context_t ctx;
        unsigned nr_events = 10;

        memset(&ctx, 0, sizeof(ctx));
       
  int errcode = io_setup(nr_events, &ctx);
        if (errcode == 0)
                printf("io_setup success\n");
        else
                printf("io_setup error: :%d:%s\n", errcode, strerror(-errcode));

        int fd = open("direct.txt", O_CREAT|O_DIRECT|O_WRONLY, S_IRWXU|S_IRWXG|S_IROTH);
        printf("open: %s\n", strerror(errno));

        char * buf;
        errcode = posix_memalign((void**)&buf, sysconf(_SC_PAGESIZE), sysconf(_SC_PAGESIZE));
        printf("posix_memalign: %s\n", strerror(errcode));

        strcpy(buf, "hello xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");

        struct iocb *iocbpp = (struct iocb *)malloc(sizeof(struct iocb));
        memset(iocbpp, 0, sizeof(struct iocb));

        iocbpp[0].data           = buf;
        iocbpp[0].aio_lio_opcode = IO_CMD_PWRITE;
        iocbpp[0].aio_reqprio    = 0;
        iocbpp[0].aio_fildes     = fd;

        iocbpp[0].u.c.buf    = buf;
        iocbpp[0].u.c.nbytes = sysconf(_SC_PAGESIZE);
        iocbpp[0].u.c.offset = 0;
        
  
        int n = io_submit(ctx, 1, &iocbpp);
        printf("==io_submit==: %d:\n", n);

        struct io_event events[10];
        struct timespec timeout = {1, 100};

        //n = io_getevents(ctx, 1, 10, events, &timeout);
        //printf("io_getevents: %d:\n", n);

        close(fd);
        io_destroy(ctx);

        return 0;
}
编译方法：gcc -0 myaio myaio.c -laio -D_GNU_SOURCE