Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Chapter 9 257
Intrinsics Reference (cont)
HPFOPEN
HPFOPEN
Opens a file, defines its physical characteristics, and sets up access to
the file.
Syntax
I32 I32 I32V *
HPFOPEN(filenum, status [, itemnum,item
[, itemnum,item
[, itemnum,item
.
.
.
[, itemnum,item ]...]]]);
Use
The HPFOPEN intrinsic sets up access to a file and defines its
characteristics and the manner in which it may be accessed. HPFOPEN
provides a superset of the options provided by the FOPEN intrinsic.
That is, all of the file options available through an FOPEN call are
provided, along with some additional options and enhanced features.
When these additions or enhancements apply to asynchronous device
control, they will be noted in the parameter descriptions that follow. For
a complete summary of all the additional options and features provided
by HPFOPEN you should see the MPE/iX Intrinsics Reference Manual.
NOTE Because HPFOPEN is designed to be more flexible and extensible than
the FOPEN intrinsic, HPFOPEN is the recommended intrinsic for file
access.
The HPFOPEN intrinsic uses
itemnum/item pairs to specify file
options. The
itemnum indicates the option being set, and the item
specifies the desired setting. The
itemnum/item optional parameters
must always appear in pairs, except for Item#=0,which can be used to
end the option list. You can specify up to 41 option pairs in the same
call, following the rules of precedence listed below:
•An
itemnum takes precedence over any previously specified
duplicate
itemnum . Any duplicated itemnum is flagged as a
warning.
• Some pairs are mutually exclusive. When applicable, these are noted
in the
itemnum/item summary that follows.