RSM_GET_SEGMENTID_RANGE(3RSM) Remote Shared Memory Library Functions


rsm_get_segmentid_range - get segment ID range


cc [ flag... ] file... -lrsm [ library... ]
#include <rsmapi.h>

int rsm_get_segmentid_range(const char *appid,
rsm_memseg_id_t *baseid, uint32_t *length);


RSM segment IDs can be either specified by the application or generated
by the system using the rsm_memseg_export_publish(3RSM) function.
Applications that specify segment IDs require a reserved range of segment
IDs that they can use. This can be achieved by using
rsm_get_segmentid_range() and by reserving a range of segment IDs in the
segment ID configuration file, /etc/rsm/rsm.segmentid. The
rsm_get_segmentid_range() function can be used by applications to obtain
the segment ID range reserved for them. The appid argument is a null-
terminated string that identifies the application. The baseid argument
points to the location where the starting segment ID of the reserved
range is returned. The length argument points to the location where the
number of reserved segment IDs is returned.

The application can use any value starting at baseid and less than
baseid+length. The application should use an offset within the range of
reserved segment IDs to obtain a segment ID such that if the baseid or
length is modified, it will still be within its reserved range.

It is the responsibility of the system administrator to make sure that
the segment ID ranges are properly administered (such that they are non-
overlapping, the file on various nodes of the cluster have identical
entries, and so forth.) Entries in the /etc/rsm/rsm.segmentid file are of
the form:

#keyword appid baseid length
reserved SUNWfoo 0x600000 1000

The fields in the file are separated by tabs or blanks. The first string
is a keyword "reserve", followed by the application identifier (a string
without spaces), the baseid (the starting segment ID of the reserved
range in hexadecimal), and the length (the number of segmentids
reserved). Comment lines contain a "#" in the first column. The file
should not contain blank or empty lines. Segment IDs reserved for the
system are defined in the </usr/include/rsm/rsm_common.h> header and
cannot be used by the applications.


Upon successful completion, these functions return 0. Otherwise, an error
value is returned to indicate the error.


The rsm_get_segmentid_range() function can return the following errors:

The address passed is invalid.

The appid is not defined in configuration file.

The configuration file is not present or not
readable, or the configuration file format is


See attributes(5) for descriptions of the following attributes:

|Interface Stability | Unstable |
|MT-Level | MT-Safe |


rsm_memseg_export_publish(3RSM), attributes(5)