Performs read and write on an open file with arguments passed in a uio structure.
#include <sys/types.h> #include <sys/errno.h>
int fp_rwuio (fp, rw, uiop, ext) struct file *fp; enum uio_rw rw; struct uio *uiop; int ext;
| fp | Points to a file structure returned by the fp_open or fp_opendev kernel service. |
| rw | Indicates whether this is a read operation or a write operation. It has a value of UIO_READ or UIO_WRITE. |
| uiop | Points to a uio structure, which contains information such as where to move data and how much to move. |
| ext | Specifies an extension argument required by some device drivers. Its content, form, and use are determined by the individual driver. |
The fp_rwuio kernel service is not the preferred interface for read and write operations. The fp_rwuio kernel service should only be used if the calling routine has been passed a uio structure. If the calling routine has not been passed a uio structure, it should not attempt to construct one and call the fp_rwuio kernel service with it. Rather, it should pass the requisite uio components to the fp_read or fp_write kernel services.
The fp_rwuio kernel service can be called from the process environment only.
| 0 | Indicates a successful operation. |
If an error occurs, one of the values from the /usr/include/sys/errno.h file is returned.
The fp_rwuio kernel service is part of Base Operating System (BOS) Runtime.
The uio structure.
Logical File System Kernel Services in AIX Version 4.3 Kernel Extensions and Device Support Programming Concepts.