FORTRAN Reference Manual

Mixed-Language Programming
FORTRAN Reference Manual—528615-001
13-18
Calling TAL Subprograms From FORTRAN
If you compile your FORTRAN modules with ENV OLD in effect and your TAL modules
with either ENV OLD or ENV NEUTRAL in effect, routines written in both languages
can open the same file but each open is independent of all other opens.
You can share access to the same file open by passing the file number between
routines that need to access the same file using the same file open.
If you compile your FORTRAN modules with ENV COMMON and your TAL modules
with either ENV COMMON or ENV NEUTRAL, your FORTRAN and TAL routines can
share access to the same Guardian file open for standard input and for standard
output—the files associated with unit 5 and unit 6, respectively. To share standard input
or standard output, a routine in each language must explicitly open the file.
The TAL procedures can use the Guardian file system, the Sequential Input/Output
(SIO) package of GPLIB, or embedded NonStop SQL statements without interfering
with FORTRAN I/O statements in the same program.
For more information about shared files, see the OPEN Statement on page 7-70.
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If the FORTRAN program does not declare the TAL procedure with a GUARDIAN
or CONSULT directive:
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If the FORTRAN program is compiled with any EXTENDEDREF,
LARGECOMMON, or LARGEDATA directives, the called TAL procedure must
declare all reference parameters (if any) with .EXT, so the TAL procedure will
expect the doubleword argument addresses that FORTRAN provides.
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Otherwise, the called TAL procedure must declare all reference parameters (if
any) without .EXT, so the TAL procedure will expect the word-address
arguments that FORTRAN provides in this case.
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For a TAL type UNSIGNED(8) formal parameter passed by value, FORTRAN
allows a CHARACTER*1 expression or an integer constant with value in the range
0 through 255 as the argument.
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For a TAL type UNSIGNED(16) formal parameter passed by value, FORTRAN
allows an integer constant with value in the range 0 through 65,535 as the
argument.
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For a TAL type UNSIGNED(31) formal parameter passed by value, FORTRAN
allows an integer constant with value in the range 0 through 3,147,483,647 as the
argument.
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If a called TAL procedure has parameter-pair formal parameters, FORTRAN
generates an address-length pair actual parameter on the stack according to the