Stores a byte of data in user memory.
#include <sys/types.h> #include <sys/errno.h>
int subyte (uaddr, c) uchar *uaddr; uchar c;
|uaddr||Specifies the address of user data.|
|c||Specifies the character to store.|
The subyte kernel service stores a byte of data at the specified address in user memory. It is provided so that system calls and device heads can safely access user data. The subyte service ensures that the user has the appropriate authority to:
The subyte service should only be called while executing in kernel mode in the user process.
The subyte kernel service can be called from the process environment only.
|0||Indicates successful completion.|
|-1||Indicates a uaddr parameter that is not valid for one of the following reasons:|
The subyte kernel service is part of Base Operating System (BOS) Runtime.
The fubyte kernel service, fuword kernel service, suword kernel service.
Accessing User-Mode Data While in Kernel Mode and Memory Kernel Services in AIX Kernel Extensions and Device Support Programming Concepts.