Large File-Enabled Asynchronous I/O
The fundamental data structure associated with all AIO operations is struct aiocb. Within this structure is the aio_offset field, which is used to specify the offset for an I/O operation.
Due to the signed 32-bit definition of aio_offset, the default AIO interfaces are limited to an offset of 2Gb minus 1. To overcome this limitation, a new AIO control block with a signed 64-bit offset field and a new set of AIO interfaces has been defined. These 64-bit definitions end with "64."
The large offset-enabled AIO interfaces are available under the _LARGE_FILES compilation environment and under the _LARGE_FILE_API programming environment. For further information, see Writing Programs That Access Large Files in AIX® Version 7.1 General Programming Concepts: Writing and Debugging Programs.
Under the _LARGE_FILES compilation environment, AIO applications written to the default interfaces interpret the following redefinitions:
| Item | Redefined To Be | Header File |
|---|---|---|
| struct aiocb | struct aiocb64 | sys/aio.h |
| aio_read() | aio_read64() | sys/aio.h |
| aio_write() | aio_write64() | sys/aio.h |
| aio_cancel() | aio_cancel64() | sys/aio.h |
| aio_suspend() | aio_suspend64() | sys/aio.h |
| aio_listio() | aio_listio64() | sys/aio.h |
| aio_return() | aio_return64() | sys/aio.h |
| aio_error() | aio_error64() | sys/aio.h |
For information on using the _LARGE_FILES environment, see Porting Applications to the Large File Environment in AIX Version 7.1 General Programming Concepts: Writing and Debugging Programs.
In the _LARGE_FILE_API environment, the 64-bit application programming interfaces (APIs) are visible. This environment requires recoding of applications to the new 64-bit API name. For further information on using the _LARGE_FILE_API environment, see Using the 64-Bit File System Subroutines in AIX Version 7.1 General Programming Concepts: Writing and Debugging Programs.