FORTRAN Reference Manual

Compiler Directives
FORTRAN Reference Manual—528615-001
10-30
HIGHCOMMON Compiler Directive
If you specify ENV COMMON, HIGHBUFFER specifies the size of the
#CRE_HEAP data block. #CRE_HEAP contains the private data used by the CRE.
If you do not specify HIGHBUFFER, FORTRAN allocates 1,024 words in
#CRE_HEAP. If you specify HIGHBUFFER in a program that specifies ENV
COMMON, always specify a minimum of 1,024 bytes for size.
Considerations
•
Your program requires more memory for HIGHBUFFER if you compile your
program with ENV COMMON in effect than it does if you compile with ENV OLD in
effect.
•
The layout of the memory allocated when you specify ENV COMMON is different
than the layout if you specify ENV OLD or do not specify an ENV directive.
•
For additional information on buffer pools, see Section 12, Memory Organization.
Example
?HIGHBUFFER 1066
HIGHCOMMON Compiler Directive
The HIGHCOMMON directive allocates common storage in upper data memory for
specified common blocks.
block-name
is a common block name.
Considerations
•
The HIGHCOMMON directive must appear before the END statement of the first
subprogram that declares the block specified in the directive.
•
If you omit the HIGHCOMMON directive, the compiler allocates all COMMON
blocks in the lower half of the user data segment or in the extended data segment
depending on the LARGECOMMON directive.
•
If the HIGHCOMMON directive includes a list of block names, the compiler
allocates those blocks in the upper half of the user data segment, and allocates all
other blocks in the lower half, or in the extended data segment, depending on the
LARGECOMMON directive.
•
If you do not specify any common block names for the HIGHCOMMON directive,
the compiler allocates all word-addressed blocks in the upper half of the user data
HIGHCOMMON
block name–
block name , block name–[]. . .–()