statgrab — get system statistics
#include <statgrab.h>
int sg_init();
int sg_drop_privileges();
sg_error sg_get_error();
const char *sg_get_error_arg();
intsg_get_error_errno();
const char *sg_str_error(code);
sg_error code;
sg_cpu_stats *sg_get_cpu_stats();
sg_cpu_stats *sg_get_cpu_stats_diff();
sg_cpu_percents *sg_get_cpu_percents();
sg_disk_io_stats *sg_get_disk_io_stats( | entries); |
| int * | entries; |
sg_disk_io_stats *sg_get_disk_io_stats_diff( | entries); |
| int * | entries; |
sg_fs_stats *sg_get_fs_stats();
sg_host_info *sg_get_host_info();
sg_load_stats *sg_get_load_stats();
sg_mem_stats *sg_get_mem_stats();
sg_swap_stats *sg_get_swap_stats();
sg_network_io_stats *sg_get_network_io_stats( | entries); |
| int * | entries; |
sg_network_io_stats *sg_get_network_io_stats_diff( | entries); |
| int * | entries; |
sg_network_iface_stats *sg_get_network_iface_stats( | entries); |
| int * | entries; |
sg_page_stats *sg_get_page_stats();
sg_page_stats *sg_get_page_stats_diff();
sg_process_count *sg_get_process_stats();
sg_user_stats *sg_get_user_stats();
The statgrab library provides a cross-platform interface to getting system statistics. Each of the function calls returns a structure containing 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.