Obtain information stored in the system page.
#include <sys/procfs.h> #define DCMD_PROC_SYSINFO __DIOF(_DCMD_PROC, __PROC_SUBCMD_PROCFS + 0, procfs_sysinfo)
The arguments to devctl() are:
| Argument | Value |
|---|---|
| filedes | A file descriptor for the process. |
| dcmd | DCMD_PROC_SYSINFO |
| dev_data_ptr | NULL, or an array of procfs_sysinfo structures |
| n_bytes | 0, or the size of the array |
| dev_info_ptr | A pointer to an integer where the required size can be stored |
The argument is a pointer to a procfs_sysinfo structure that's filled in with the required information upon return. To get the whole system page, you have to make two calls: the first gets the size required:
devctl( fd, DCMD_PROC_SYSINFO, NULL, 0, &totalsize );
You then allocate a buffer of the required size and pass that buffer to the second call:
buffer = malloc( totalsize ); devctl( fd, DCMD_PROC_SYSINFO, buffer, totalsize, NULL );
The procfs_sysinfo structure is the same as the system page; for more information, see the System Page chapter of Building Embedded Systems.