Проект OpenNet: MAN rctl_walk (3) Библиотечные вызовы (FreeBSD и Linux)

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rctl_walk (3)

>> rctl_walk (3) ( Solaris man: Библиотечные вызовы )

NAME

rctl_walk - visit registered rctls on current system

SYNOPSIS

#include <rctl.h>

int rctl_walk(int (*callback)(const char *rctlname, void *walk_data),
    void *init_data);

DESCRIPTION

The rctl_walk() function provides a mechanism for the application author to examine all active resource controls (rctls) on the current system. The callback function provided by the application is given the name of an rctl at each invocation and can use the walk_data to record its own state. The callback function should return non-zero if it encounters an error condition or attempts to terminate the walk prematurely; otherwise the callback function should return 0.

RETURN VALUES

Upon successful completion, rctl_walk() returns 0. It returns -1 if the callback function returned a non-zero value or if the walk encountered an error, in which case errno is set to indicate the error.

ERRORS

The rctl_walk() function will fail if:

ENOMEM

: There is insufficient memory available to set up the initial data for the walk.

Other returned error values are presumably caused by the callback function.

EXAMPLES

Example 1 Count the number of rctls available on the system.

The following example counts the number of resource controls on the system.

#include <sys/types.h>
#include <rctl.h>
#include <stdio.h>

typedef struct wdata {
    uint_t count;
} wdata_t;

wdata_t total_count;

int
simple_callback(const char *name, void *pvt)
{
    wdata_t *w = (wdata_t *)pvt;
    w->count++;
    return (0);
}

...

total_count.count = 0;
errno = 0;
if (rctl_walk(simple_callback, &total_count)) == 0)
    (void) printf("count = %u\n", total_count.count);