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PREPRM, PREPRO, PREPF$, and POSTPR$
PREPRM dynamically attaches internal filenames to the filenames specified in the first
two fields as follows: SI$$ is attached to field-1 and SO$$ is attached to field-2.
field-1 (SI) is expected to contain the symbolic input to the processor. PREPRM checks
that the element specified is typed as symbolic (element type 01).
field-2 (SO) is typically used for the updated symbolic output element if corrections have
been applied to the input symbolic element in field-1 (SI). This would apply if the routine
SIR$ will be used. However, field-2 (SO) may be used for other types of output
elements.
The mnemonics SI, RO, and SO appear in error messages output by PREPRO and
PREPRM. They refer to the first three fields on the processor call statement as follows:
SI field-1
RO field-2
SO field-2 if PREPRM is used; field-3 if PREPRO is used
14.1.1. PREPRO–Preprocessor Routine
PREPRO reads the processor call statement in internal format (INFOR) (see Section 12),
standardizes its form in PARTBL (see Figure 14-1), and dynamically assigns the
necessary files. PREPRO obtains the “next write location” for program files and, for
tape files, verifies that the source input element exists.
Initial Conditions
The processor must call PREPRO before it executes any read command such as
ER SYMB$ (READ$ function), ER AREAD$, or ER READ$.
The parameter table PARTBL must be externally defined and at least 40 words long. It
also should be zero-filled.
Calling Sequence
LMJ X11,PREPRO$
error return
normal return
Error Return
The error return is taken under the following conditions:
I/O error occurs (A0 = 0)
error when reading INFOR (A0 ≠ 0)
tape positioned improperly (A0 ≠ 0)
file does not exist (A0 ≠ 0)
file is not a program file (A0 ≠ 0)
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