Intel® oneAPI DPC++/C++ Compiler Developer Guide and Reference

Development Reference Guides

Contents

aio_read

Performs an asynchronous read operation.

Syntax

int aio_read(struct aiocb *aiocbp);
Description
The
aio_read()
 function requests an asynchronous read operation, calling the function, 
"ReadFile(hFile, lpBuffer, nNumberOfBytesToRead, lpNumberOfBytesRead, NULL);"
where,
  • hFile
     is given by
    aiocbp->aio_fildes
  • lpBuffer
     is given by
    aiocbp->aio_buf
  • nNumberOfBytesToRead
     is given by
    aiocbp->aio_nbytes
Use the function
aio_return()
 to retrieve the actual bytes read in
lpNumberOfBytesRead
.
Use the extension
aiocb->aio_offset == (intptr_t)-1
 to start the read operation after the last read record. This extension avoids extra file positioning and enhances performance.
Returns
0
: On success
-1
: On error
To get the correct error code, use
errno.
 To get the error that occurred during asynchronous read operation, use
aio_error()
 function.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.