cpu_foreach(3) Library Functions Manual cpu_foreach(3)
NAME
cpu_foreach - enumerate members of a CPU set (libc library)
SYNOPSIS
#include <cpuset.h>
cpu_cursor_t cursor = SET_CURSOR_INIT;
cpuid_t cpu_foreach(
cpuset_t cpuset,
int flags,
cpu_cursor_t *cursor );
PARAMETERS
Specifies a CPU set whose members are to be enumerated. Control the processing of set members. The flags parameter can be one or more (a
logical OR operation) of the following flags: Initializes the cursor to the first member of the set before scanning. Wraps around to the
beginning of the set when scanning for members. Consumes the set members; that is, removes the member from the set when found. As shown
in the SYNOPSIS, a cursor variable may be initialized to the value SET_CURSOR_INIT. Initialization of this variable is equivalent to set-
ting the SET_CURSOR_FIRST flag on the initial call to cpu_foreach(). Points to an opaque type that records the position in a set for sub-
sequent invocations of the cpu_foreach() function.
DESCRIPTION
The cpu_foreach() function scans the specified cpuset, starting at the position saved in the cursor parameter, for members of the set and
returns the first member found. If the SET_CURSOR_FIRST flag is set, the cursor is initialized to the beginning of the set before starting
the scan. If no members are found, the cpu_foreach() function will return CPU_NONE.
If the SET_CURSOR_WRAP flag is set, the scan will wrap from the end of the set to the beginning searching for a member to return. Other-
wise, a one pass scan is performed, and when the end of the set is reached, the cursor is positioned at the end of the set. From then on,
the cpu_foreach() function will continue to return CPU_NONE until the cursor is reinitialized (by specifying the SET_CURSOR_FIRST
orSET_CURSOR_WRAP flag).
If the SET_CURSOR_CONSUME flag is set, the member returned, if any, will be removed from the set.
NOTES
Although the preceding description discusses the "beginning" and "end" of the set, and wrapping from the end to the beginning, CPU sets are
conceptually unordered. Thus, these end points are arbitrary points in the set that exist to ensure that each member is returned only once
per pass through the set. Therefore, applications should not depend on a specific numeric order of the returned member IDs.
RETURN VALUES
The cpu_foreach() function returns the next member in the set starting at the position of the cursor. If no more members are found,
CPU_NONE is returned. This function always completes successfully.
ERRORS
No errors are defined for the cpu_foreach() function.
EXAMPLES
See the EXAMPLES section of cpusetops(3) for a sample program that uses the cpu_foreach() function.
SEE ALSO
Functions: cpusetops(3), numa_intro(3)
Files: numa_types(4)
cpu_foreach(3)
