table(2) System Calls Manual table(2)
NAME
table - Examines or updates elements from a system table.
SYNOPSIS
#include <sys/table.h>
int table(id, index, addr, nel, lel) long id; long index; void *addr; long nel; u_long lel;
PARAMETERS
The ID of the system table that contains the element or elements. The index of an element within the table. The address of a struct (or a
struct array) of the appropriate type to copy the element values to (on examine) or from (on update). The various structure layouts are
described in /usr/include/sys/table.h. A signed number that specifies how many elements to copy and in which direction. A positive value
copies the elements from the kernel to addr. A negative value copies the elements from addr to the kernel. The expected size of a single
element.
DESCRIPTION
The table() interface is used to examine or update one or more elements in the system table. The system table is specified by id and the
starting element is specified by index.
The table() interface copies the element value or values to or from the specified addr. The nel parameter specifies the number of elements
to copy, starting from index. A positive value indicates an examine operation. The elements are copied from the kernel to addr. A nega-
tive value indicates an update operation. The elements are copied from addr to the kernel.
The lel parameter specifies the expected element size. If multiple elements are specified, successive addresses are calculated for addr by
incrementing it by lel for each element copied. If the size of a given element is larger than lel, table() truncates excess data on an
update (from addr to the kernel) and stores only the expected size on an examine (from the kernel to addr). If the size of a given element
is smaller than lel, table() copies only the valid data on an update and pads the element value on an examine.
The table() interface guarantees that an update operation will not change the offset and size of any field within an element. New fields
are added only at the end of an element.
The table() interface returns a count of the elements examined or updated. The id TBL_PROCINFO allows you to determine the actual number
of elements in a table before requesting any data; call table() with lel set to zero (0) and nel to the maximum positive integer.
The id parameter must specify one of the following tables, each of which has a structure in <sys/table.h>, unless otherwise noted: The con-
trolling terminal device number table. The index is by process ID and exactly one element can be requested. If the process ID is zero
(0), the current process is indexed. Only 0 and the current process ID are supported. The element is of type dev_t as defined in
<sys/types.h>. This table is examine only. It cannot be updated. The U-area table. The index is by process ID. See the user.h header
file for the (pseudo) struct user that is returned. The system load average vector (pseudo) table. The index must be zero (0) and exactly
one element can be requested.
If the scale is zero (0), the load average vector is the floating point variant. If the size is non-zero, the load average vector
has been scaled by the indicated factor (typically 1000) to produce the long integer variant. This table is examine only. It can-
not be updated. The system include file version number (pseudo) table. The index must be zero (0) and exactly one element can be
requested. The include version is a unique integer. It identifies the layout of kernel data structures that are imported by cer-
tain kernel-dependent programs. This table is examine only. It cannot be updated. The process command argument table containing
the saved arguments for processes. The index is by process ID and exactly one element can be requested. Arguments for processes
other than the current process can be accessed only by the root user. This table is examine only. It cannot be updated.
All the command line arguments for the process. Specify the process id in the index argument. The addr argument points to a buf-
fer into which the command line arguments are placed.
The amount of buffer space needed for the command line arguments depends on the total length of all the arguments from the process
being examined. Specify the size of the user buffer with the lel argument. If the buffer is not large enough to accept the com-
plete argument list, the given length of the buffer is copied.
The arguments are placed in the buffer as a series of null-terminated strings, in argument order. The maximum process count per
user ID table. The index is by process ID and exactly one element can be requested. If the process ID is zero (0), the current
process is indexed. Only 0 and the current process ID are supported. The element is of the short integer type.
The maximum count includes all processes running under the current user ID even though the limit affects only the current process
and any children created with that limit in effect. The limit can be changed only by the root user. The process status information
table. The index is an offset into a table of processes. Status information for processes other than the current process can be
accessed only by the root user. This table is examine only and cannot be updated.
This id lets you determine the actual number of elements in a table before you request any data. You call table with the lel argu-
ment set to zero, index set to zero, and the nel argument set to the maximum positive integer. The return is the number of elements
in the table. The current count of threads and their states. The index may be either a single process ID, or zero (0) to count all
process IDs. Only the root user can obtain information on a single process ID that is not the current process. Only one element
should be requested (only one is available). This table is examine only. It cannot be updated. The process environment table.
The index is by process ID and exactly one element can be requested. Environment information for processes other than the current
process can be accessed only by the root user. This table is examine only. It cannot be updated. The system time information ta-
ble. The index must be zero (0) and exactly one element can be requested. The system information table contains ticks of time
accumulated in the various system states: user, nice, system, and idle. The system tick frequency and profiling (if configured)
frequency are also provided for conversion from ticks to time values. This table is examine only. It cannot be updated. The disk
statistics table. The index is by disk number. This table is examine only. It cannot be updated. The system swap device list
information table. This table is examine only. It cannot be updated. If the index is positive or zero (0), the swap device informa-
tion for the entry in the swap device list is returned.
If the index is less than zero (0), the amount of total swap space configured and amount of total free space on the system is
returned. In addition, the flags field contains the value of vm_swap_eager flag and the dev field contains the lazy swap device num-
ber (if lazy swap) or zero (0) (if eager swap). The TTY statistics table. The index must be zero (0) and exactly one element can
be requested. This table is examine only. It cannot be updated. The message queue ID table. The index is the index into the
queue array. Each element is a msqid_ds structure as defined in msqid_ds(). This table is examine only. Its elements cannot be
updated. The semaphore ID table. The index is the index into the array of semaphore IDs. Each element is a semid_ds structure as
defined in semid_ds(). This table is examine only. Its elements cannot be updated. The shared memory region ID table. The index
is the index into the array of shared memory region IDs. Each element is a shmid_ds structure as defined in shmid_ds(). This table
is examine only. Its elements cannot be updated. The message information table. This table is examine only. Its elements cannot
be updated. The message information structure is defined in <sys/msg.h>.
The index is by field positions within the message information structure, as follows: The maximum message size The maximum number of
bytes on the queue The number of message queue identifiers The number of system message headers The semaphore information table.
This table is examine only. It cannot be updated. The semaphore information structure is defined in <sys/sem.h>.
The index is by field position within the semaphore information structure as follows: The number of semaphore identifiers The maxi-
mum number of semaphores per identifier The maximum number of operations per semop() call The maximum number of undo entries per
process The semaphore maximum value The maximum adjust on exit value The shared memory information table. This table is examine
only. It cannot be updated. The shared memory information structure is defined in <sys/shm.h>.
The index is by field position within the shared memory information structure, as follows:
The maximum shared memory region size The minimum shared memory region size The number of shared memory identifiers The maximum num-
ber of attached shared memory regions per process The system interrupt information table. There is no index into the table. This
table is examine only. It cannot be updated. The user file table. The index is by process ID and exactly one element can be
requested. The addr argument is of type struct stat. The nel argument specifies the file descriptor. This operation provides stat
information on the specified descriptor for the specified process ID. Information on processes other than the current process can
be accessed only by the superuser. This table is examine only.
RETURN VALUES
A positive return value indicates that the call succeeded for that number of elements. A return value of -1 indicates that an error
occurred, and an error code is stored in the global location errno.
ERRORS
The addr parameter specifies an invalid address. The table specified by id is not defined. The index value is not valid for the specified
table. The specified table allows only an index of the current process ID with exactly one element. Some other index or element number
was specified. An element length of zero (0) was supplied for the TBL_ARGUMENTS table. An attempt was made to update an examine-only ta-
ble. An attempt was made to change the maximum number of processes or the account ID, and the caller was not the root user. The process
specified by a process ID index cannot be found.
RELATED INFORMATION
acct(2) delim off
table(2)