#include <statgrab.h>
sg_disk_io_stats *sg_get_disk_io_stats(int *entries);
sg_disk_io_stats *sg_get_disk_io_stats_diff(int *entries);
sg_get_disk_io_stats returns the disk IO stored in the kernel which holds the amount of data transferred since bootup. On some platforms, such as Solaris 7, this value is stored in a 32bit int, so wraps around when it reaches 4GB. Other platforms, such as Solaris 8, hold the value in a 64bit int, which wraps somewhere near 17 million terabytes.
sg_get_disk_io_stats_diff is the same as sg_get_disk_io_stats except it will return the difference since the last call. So, for instance a call to sg_get_disk_io_stats_diff is made, and called again 5 seconds later. Over that time, 2000 bytes of traffic were written and 10000 bytes read. write_bytes will store 2000 bytes, read_bytes will store 10000, and systime will store 5. This function copes with wrap arounds by the O/S so should be seemless to use.
On Solaris libstatgrab will attempt to get the cXtXdXsX representation for the disk_name string. If it fails it will use a name like sd0. On some systems programs calling libstatgrab will need elevated privileges to lookup some of the names. The mappings are built up when sg_init is called.
typedef struct{
char *disk_name;
long long read_bytes;
long long write_bytes;
time_t systime;
}sg_disk_io_stats;
On operating systems that hold only 32bits of data there is a problem if the values wrap twice. For example, on Solaris 7 if 9GB is transferred and the operating system wraps at 4GB, the sg_get_disk_io_stats_diff function will return 5GB.