RSM_MEMSEG_IMPORT_GET(3RSM) Remote Shared Memory Library Functions


NAME


rsm_memseg_import_get, rsm_memseg_import_get8, rsm_memseg_import_get16,
rsm_memseg_import_get32, rsm_memseg_import_get64 - read from a segment

SYNOPSIS


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

int rsm_memseg_import_get(rsm_memseg_import_handle_t im_memseg,
off_t offset, void *dest_addr, size_t length);


int rsm_memseg_import_get8(rsm_memseg_import_handle_t im_memseg,
off_t offset, uint8_t *datap, ulong_t rep_cnt);


int rsm_memseg_import_get16(rsm_memseg_import_handle_t im_memseg,
off_t offset, uint16_t *datap, ulong_t rep_cnt);


int rsm_memseg_import_get32(rsm_memseg_import_handle_t im_memseg,
off_t offset, uint32_t *datap, ulong_t rep_cnt);


int rsm_memseg_import_get64(rsm_memseg_import_handle_t im_memseg,
off_t offset, uint64_t *datap, ulong_t rep_cnt);


DESCRIPTION


When using interconnects that allow memory mapping (see
rsm_memseg_import_map(3RSM)), standard CPU memory operations may be used
for accessing memory of a segment. If a mapping is not provided, then
explicitly calling these functions facilitates reading from a segment.
Depending on the attributes of the extension library of the specific
interconnect, these functions may involve performing an implicit mapping
before performing the data transfer. Applications can be made
interconnect-independent with respect to segment reads by using these
functions. The data access error detection is performed through the use
of barriers (see rsm_memseg_import_open_barrier(3RSM)). The default
barrier operation mode is RSM_BARRIER_MODE_IMPLICIT, meaning that around
every get operation open and close barrier are performed automatically.
Alternatively, explicit error handling may be set up for these functions
(see rsm_memseg_import_set_mode(3RSM)). In either case the barrier should
be initialized prior to using these functions using
rsm_memseg_import_init_barrier(3RSM).


The rsm_memseg_import_get() function copies length bytes from the
imported segment im_memseg beginning at location offset from the start of
the segment to a local memory buffer pointed to by dest_addr.


The rsm_memseg_import_get8() function copies rep_cnt number of 8-bit
quantities from successive locations starting from offset in the imported
segment to successive local memory locations pointed to by datap.


The rsm_memseg_import_get16() functions copies rep_cnt number of 16-bit
quantities from successive locations starting from offset in the imported
segment to successive local memory locations pointed to by datap. The
offset must be aligned at half-word address boundary.


The rsm_memseg_import_get32() function copies rep_cnt number of 32-bit
quantities from successive locations starting from offset in the imported
segment to successive local memory locations pointed to by datap. The
offset must be aligned at word address boundary.


The rsm_memseg_import_get64() function copies rep_cnt number of -bit
quantities from successive locations starting from offset in the imported
segment to successive local memory locations pointed to by datap. The
offset must be aligned at double-word address boundary.


The data transfer functions that transfer small quantities of data (that
is, 8-, 16-, 32-, and 64-bit quantities) perform byte swapping prior to
the data transfer, in the event that the source and destination have
incompatible endian characteristics.

RETURN VALUES


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

ERRORS


These functions can return the following errors:

RSMERR_BAD_SEG_HNDL

Invalid segment handle.


RSMERR_BAD_ADDR

Bad address.


RSMERR_BAD_MEM_ALIGNMENT

Invalid memory alignment for pointer.


RSMERR_BAD_OFFSET

Invalid offset.


RSMERR_BAD_LENGTH

Invalid length.


RSMERR_PERM_DENIED

Permission denied.


RSMERR_INSUFFICIENT_RESOURCES

Insufficient resources.


RSMERR_BARRIER_UNINITIALIZED

Barrier not initialized.


RSMERR_BARRIER_FAILURE

I/O completion error.


RSMERR_CONN_ABORTED

Connection aborted.


ATTRIBUTES


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


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Evolving |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO


rsm_memseg_import_init_barrier(3RSM),
rsm_memseg_import_open_barrier(3RSM), rsm_memseg_import_set_mode(3RSM),
attributes(5)


June 8, 2001 RSM_MEMSEG_IMPORT_GET(3RSM)