Orace开源的异步IO编程库，特点是接口非常简单

官网：https://oss.oracle.com/projects/libaio-oracle/，正如标题所说，非常简单了，不用多解释，请直接看头文件，其中aio_poll类似于poll，重要的结构是aiocb64，类似于epoll_event。

#ifndef _SKGAIO_H#define _SKGAIO_H#define IOCB_CMD_READ0#define IOCB_CMD_WRITE1#define IOCB_CMD_NOP2#define IOCB_CMD_CANCEL3#define IOCB_CMD_FSYNC4#define IOCB_CMD_FDSYNC5#define IOCB_CMD_RUNNING6#define IOCB_CMD_DONE7/* Maximum number of events to retrieve at once */#define MAX_EVENTS 512#define MAX_AIO_REAP MAX_EVENTS#include <stdlib.h>#include <asm/unistd.h>#include <linux/types.h>#include <signal.h>/* * we always use a 64bit off_t when communicating * with userland.  its up to libraries to do the * proper padding and aio_error abstraction * * FIXME: this must change from glibc's definition * as we do *not* use the sigevent structure which * is big and bloated. */struct aiocb64 {  int aio_fildes;               /* File desriptor.  */  short aio_lio_opcode;           /* Operation to be performed.  */  short aio_reqprio;              /* Request priority offset.  */  void *aio_buf;       /* Location of buffer.  */  size_t aio_nbytes;            /* Length of transfer.  */  loff_t aio_offset;/* File offset.  */  /* these are internal to the kernel/libc. */  long __aio_key; // kernel sets this to -1 if completed  // otherwise >= 0 (the request#)  void * __aio_data;  // pointer to be returned in event's data   int __error_code;};#ifdef DEBUG#define dbg_printf(fmt,arg...)\printf(fmt, ##arg)#else#define dbg_printf(fmt,arg...)\do { } while(0);#endif#define aiocb aiocb64#define aio_read aio_read64#define aio_write aio_write64#define aio_poll aio_poll64#define aio_error aio_error64#define aio_return aio_return64#define aio_cancel aio_cancel64#define aio_suspend aio_suspend64#definelio_listiolio_listio64 #define aio_reap        aio_reap64/*  Initialize async i/o with the given maximum number of requests */int aio_init(int max_requests);/* Enqueue read request for given number of bytes and the given priority.  */int aio_read64(struct aiocb64 *aiocbp);/* Enqueue write request for given number of bytes and the given priority.  */int aio_write64(struct aiocb64 *aiocbp);/* Enqueue a poll request for a given fd. */int aio_poll64(struct aiocb64 *aiocbp); /* * Returns the status of the aiocb. * If the operation is incomplete, the return value is undefined * < -1 is -errno for the call. * >= -1 is the return code of the completed operation */ssize_t aio_return64(struct aiocb64 *aiocbp);/* * Returns the error status of the aiocb. * < 0 is -errno for the call. * 0 is successfully complete * EINPROGRESS is not complete at all. * > 0 is errno for unsuccessful completion. */int aio_error64(struct aiocb64 *aiocbp);/* * Try to cancel asynchronous I/O requests outstanding against file * descriptor FILDES. */int aio_cancel64 ( int fildes,  struct aiocb64 *aiocbp); /* * Suspend calling thread until at least one of the asynchronous I/O * operations referenced by LIST has completed. */int aio_suspend64(const struct aiocb64 * const list[],int nent,  const struct timespec *timeout); /* * Suspend calling thread until waitfor asynchronouse I/O operations * outstanding have completed. */int aio_reap64(struct timespec *timeout, int waitfor,               struct aiocb *out_list[], int listsize,               int *completed_count);int lio_listio64(int mode, struct aiocb64 * const list[], int nent,                 struct sigevent *__restrict __sig); /* Operation codes for `aio_lio_opcode'.  */enum{    LIO_READ,#define LIO_READ LIO_READ    LIO_WRITE,#define LIO_WRITE LIO_WRITE    LIO_NOP,#define LIO_NOP LIO_NOP    LIO_POLL,#define LIO_POLL LIO_POLL}; /* Return values of cancelation function.  */enum{    AIO_CANCELED,#define AIO_CANCELED AIO_CANCELED    AIO_NOTCANCELED,#define AIO_NOTCANCELED AIO_NOTCANCELED    AIO_ALLDONE#define AIO_ALLDONE AIO_ALLDONE}; /* Synchronization options for `lio_listio' function.  */enum{    LIO_WAIT,#define LIO_WAIT LIO_WAIT    LIO_NOWAIT#define LIO_NOWAIT LIO_NOWAIT};#endif /* _SKGAIO_H */