sg_get_disk_io_stats(3) [debian man page]

sg_get_disk_io_stats(3) 				     Library Functions Manual					   sg_get_disk_io_stats(3)

NAME

       sg_get_disk_io_stats, sg_get_disk_io_stats_diff - get disk io statistics

SYNOPSIS

       #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);

DESCRIPTION

       Both  calls  take  a  pointer to an int, entries, which is filled with the number of disks the machine has. This is needed to know how many
       sg_disk_io_stats structures have been returned. A pointer is returned to the first sg_disk_io_stats.

       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.

RETURN VALUES

       All diskio statistics return a pointer to a structure of type sg_disk_io_stats.

       typedef struct{
	       char *disk_name;
	       long long read_bytes;
	       long long write_bytes;
	       time_t systime;
       }sg_disk_io_stats;

       disk_name
	      The name known to the operating system.  (eg. on linux it might be hda)

       read_bytes
	      The number of bytes the disk has read.

       write_bytes
	      The number of bytes the disk has written.

       systime
	      The time period over which read_bytes and write_bytes were transferred.

BUGS

       On  the very first call sg_get_disk_io_stats_diff will return the same as sg_get_disk_io_stats.	After the first call it will always return
       the difference.

       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  trans-
       ferred and the operating system wraps at 4GB, the sg_get_disk_io_stats_diff function will return 5GB.

SEE ALSO

       statgrab(3)

WEBSITE

       http://www.i-scream.org/libstatgrab/

i-scream						   $Date: 2005/04/25 11:25:45 $ 				   sg_get_disk_io_stats(3)

statgrab(3)						     Library Functions Manual						       statgrab(3)

NAME

       statgrab - get system statistics

SYNOPSIS

       #include <statgrab.h>

       int sg_init(void);

       int sg_drop_privileges(void);

       sg_error sg_get_error(void);

       const char *sg_get_error_arg(void);

       intsg_get_error_errno(void);

       const char *sg_str_error(sg_error code);

       sg_cpu_stats *sg_get_cpu_stats(void);

       sg_cpu_stats *sg_get_cpu_stats_diff(void);

       sg_cpu_percents *sg_get_cpu_percents(void);

       sg_disk_io_stats *sg_get_disk_io_stats(int *entries);

       sg_disk_io_stats *sg_get_disk_io_stats_diff(int *entries);

       sg_fs_stats *sg_get_fs_stats(void);

       sg_host_info *sg_get_host_info(void);

       sg_load_stats *sg_get_load_stats(void);

       sg_mem_stats *sg_get_mem_stats(void);

       sg_swap_stats *sg_get_swap_stats(void);

       sg_network_io_stats *sg_get_network_io_stats(int *entries);

       sg_network_io_stats *sg_get_network_io_stats_diff(int *entries);

       sg_network_iface_stats *sg_get_network_iface_stats(int *entries);

       sg_page_stats *sg_get_page_stats(void);

       sg_page_stats *sg_get_page_stats_diff(void);

       sg_process_count *sg_get_process_stats(void);

       sg_user_stats *sg_get_user_stats(void);

DESCRIPTION

       The  statgrab library provides a cross-platform interface to getting system statistics. Each of the function calls returns a structure con-
       taining statistics. See the manual page for each individual function for more details on usage.

       sg_init must be the first function you call before you start to use libstatgrab; it performs all  the  one-time	initialisation	operations
       that  need  setuid/setgid  privileges.  For  instance,  on *BSD it opens a descriptor to be able to read kernel structures later on, and on
       Solaris it reads the device mappings that in some cases are only accessible by root (machines with a /dev/osa).	Once  this  has  run,  the
       other  libstatgrab  functions  no  longer  need elevated privileges. It is therefore a good idea to call sg_drop_privileges, which discards
       setuid and setgid privileges, immediately after you call sg_init, unless your application has another reason for needing setuid	or  setgid
       privileges.

       sg_init and sg_drop_privileges return 0 on success, and non-zero on failure.

       There  are  three  functions relating to error reporting in libstatgrab.  The first, sg_get_error returns an sg_error code which relates to
       the last error generated by libstatgrab. This can be converted to a string by calling sg_str_error giving the sg_error code as an argument.
       An optional argument may be set when the error was generated. This can be accessed by calling sg_get_error_arg; NULL will be returned if no
       argument has been set. Some errors will also record the value of the system errno variable when the error occurred; this can  be  retrieved
       by calling sg_get_error_errno, which will return 0 if no valid errno has been recorded.

       It is the intended practice that whenever a libstatgrab function is called and subsequently fails that an appropriate error will be set.

       The  library  was  originally  written to support the i-scream central monitoring system, but has since become a standalone package. It has
       been ported to work on Linux, NetBSD, FreeBSD, OpenBSD, DragonFly BSD, Solaris, HP-UX and Cygwin.

SEE ALSO

       sg_get_cpu_percents(3) sg_get_disk_io_stats(3) sg_get_fs_stats(3) sg_get_host_info(3) sg_get_load_stats(3) sg_get_mem_stats(3)  sg_get_net-
       work_io_stats(3) sg_get_network_iface_stats(3) sg_get_page_stats(3) sg_get_process_stats(3) sg_get_user_stats(3)

WEBSITE

       http://www.i-scream.org/libstatgrab/

i-scream						   $Date: 2005/04/25 11:25:45 $ 					       statgrab(3)