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Section 3
SYSLIB Access Methods
SYSLIB routines AEDIT$, AEDIT$F, AEDIT$SFDT, BSP$, CABSAD$, CRELAD$,
CONWRD$, FDASC$, GETPSF$, INFOR$, ID$, MFDSP$, SAR$, SDFI, SDFO, and SFDT$
are available as both relocatable and common bank routines. When using the common
bank version of these routines, the library routine is not collected into the calling
program.
The calling program contains a jump to the common bank that contains the library
routine, but the actual code of the library routine remains in the common bank. Because
the common bank code does not get collected into the calling program, as the
relocatable versions of the routines do, the calling program will be smaller. In cases
where the library routine is large, this can result in a considerable saving of space. Also,
since the common bank library routines exist independently of the calling programs, they
may be modified without forcing the calling programs to be recompiled or re-collected.
The jumps in the calling program remain valid even though the common bank code itself
changes. When transporting an absolute program from one machine to another, the
second machine must have the common bank library routines installed or the absolute
program may guard mode or produce unpredictable results.To check on whether the
SYSLIB common bank routines have been installed, it is only necessary to look for the
absolute elements SYSLIB$1, SYSLIB$2, SYSLIB$3, and SYSLIB$4 in the file that
contains the SYSLIB routines. These elements replace the SYSLIB common bank
PIRCB$. However, PIRCB$ is still included to enable programs that were collected
before the installation of SYSLIB level 75R3 to continue to run correctly.
If an installation of SYSLIB is done using COMUS level 4R2 (and higher levels), then the
SYSLIB common banks are put in the file SYS$LIB$*SYSLIB. If COMUS is not used for
the installation of SYSLIB, then the elements will be contained in the file SYS$*LIB$. All
the SYSLIB common banks have a starting address of 01000.
Table D–2 in Appendix D lists the highest address of all SYSLIB common banks. The
address of the SYSLIB level identifier is kept at 01003. The first word of the identifier is
the number of words in the identifier followed by the ASCII character representation of
the SYSLIB level (for example, 75R3).
Some of the common bank SYSLIB routines require the calling program to provide a data
area or a packet containing information that the routine needs. This area must be
contained within a bank that is write enabled and based when the SYSLIB routine is
called, and its addressing range must not overlap that of the SYSLIB common bank.
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