Performs a read on an open file with arguments passed.
#include <sys/types.h> #include <sys/errno.h>
int fp_read (fp, buf, nbytes, ext, segflag, countp)
struct file * fp;
char * buf;
int nbytes;
int ext;
int segflag;
int * countp;
| fp | Points to a file structure returned by the fp_open or fp_opendev kernel service. |
| buf | Points to the buffer where data read from the file is to be stored. |
| nbytes | Specifies the number of bytes to be read from the file into the buffer. |
| ext | Specifies an extension argument required by some device drivers. Its content, form, and use are determined by the individual driver. |
| segflag | Indicates in which part of memory the buffer specified by the buf parameter is located: |
| countp | Points to the location where the count of bytes actually read from the file is to be returned. |
The fp_read kernel service is an internal interface to the function provided by the read subroutine.
The fp_read kernel service can be called from the process environment only.
| 0 | Indicates successful completion. |
If an error occurs, one of the values from the /usr/include/sys/errno.h file is returned.
The read subroutine.
Logical File System Kernel Services in AIX 5L Version 5.2 Kernel Extensions and Device Support Programming Concepts.