Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (S)
Guardian Procedure Calls Reference Manual—522629-013
14-11
SEGMENT_ALLOCATE_ Procedure
•
Existing permanent swap file
If supplied and if
length is not 0, specifies the name of a swap file to be
associated with the segment. If used, the value of
filename must be exactly
length bytes long. If the file name is partially qualified (for example, without
the volume name), it is resolved using the contents of the =_DEFAULTS
DEFINE. All data in the file is used as initial data for the segment. Remote file
names, structured files, audited files, and files with the refresh attribute are not
accepted.
There are two advantages of using an existing swap file. First, if the file is the
required size, segment allocation cannot fail due to lack of disk space.
Second, the segment becomes a permanent repository of data.
If the process terminates without deallocating the segment, any data still in
memory is written back out to the file. Unless the segment is extensible,
SEGMENT_ALLOCATE_ must be able to allocate a sufficient number of file
extents to contain all memory in the segment.
•
New permanent swap file
If supplied, if
length is not 0, and if filename does not exist, specifies the
name of a swap file to be created. If used, the value of
filename must be
exactly
length bytes long. Remote file names are not accepted.
The advantage of using a permanent swap file is that the segment becomes a
permanent repository of data.
If the process terminates without deallocating the segment, any data still in
memory is written back out to the file. Unless the segment is extensible,
SEGMENT_ALLOCATE_ must be able to allocate a sufficient number of file
extents to contain all memory in the segment.
•
Segment sharing by the file name method
By specifying
filename, you can share the segment associated with this
swap file with another process using the same swap file (provided that both
processes have appropriate permission to the file). This is referred to as
segment sharing by the file-name method. Two processes sharing a segment
by the file-name method must be in the same processor, unless the segment is
a read-only segment. (See Considerations
on page 14-15).
error-detail output
INT .EXT:ref:1
for some returned errors, contains additional information. See
error.
pin input
INT:value