FORTRAN Reference Manual

Summary of HP Extensions
FORTRAN Reference Manual—528615-001
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Files
A record can be shorter than the entity specified in the I/O list. The formatter fills the
remainder of a short input record with blanks. For additional information, see Section 5,
Introduction to File I/O in the HP NonStop Environment.
FORMAT statements can specify binary, octal, and hexadecimal numeric conversion.
For additional information, see Section 7, Statements.
Files
Your program can use both formatted and unformatted I/O on the same file.
You can position a structured file for keyed access by using the POSITION statement.
You can update and delete records in structured files by using the UPDATE specifier
with READ and WRITE statements. For additional information, see Section 5,
Introduction to File I/O in the HP NonStop Environment, and Section 7, Statements.
Your program can open a file multiple times by having more than one UNIT reference
the file. For additional information, see Section 5, Introduction to File I/O in the
HP NonStop Environment.
The function FILENUM returns the Guardian file number associated with the specified
unit. For additional information, see Section 8, Intrinsic Functions.
The TIMEOUT specifier for the READ and WRITE statements provides timed access
to files. For additional information, see the description of the READ and WRITE
statements in Section 7, Statements.
The LENGTH specifier for the READ statement obtains the actual length of a
variablelength record. The LENGTH specifier for the WRITE statement determines the
last character position used in a data transfer to an internal file. For additional
information, see the description of the READ and WRITE statements inSection 7,
Statements.
The PROMPT and PROMPTLENGTH specifiers for the READ statement provide
prompting for input from interactive terminals. The OPEN statement’s control list
includes the optional SYNCDEPTH, PROTECT, MODE, SPACECONTROL, STACK,
and TIMED specifiers for additional file control capabilities. For more information, see
the descriptions of the READ and OPEN statements in Section 7, Statements.
Access to Operating System Procedures
Using the GUARDIAN directive described in Section 10, Compiler Directives,
FORTRAN programs can invoke Guardian procedures as subroutines or external
functions as if they were written in FORTRAN. For additional information, see
Section 13, Mixed-Language Programming, and Section 15, Utility Routines.