Performs control operations on a file or a device.
Use |
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The FCONTROL intrinsic performs various control operations
on a file or on the device on which the file resides. It applies
to files on disk and tape as well as to files on terminals and printers.
The controlcode parameter determines the
action taken by the FCONTROL call.
The following pages describe the use of the FCONTROL intrinsic
for control of asynchronous devices. Chapters 3 and 4 also include
discussions on FCONTROL. For a complete explanation of FCONTROL
functions for disk and tape files, refer to the MPE/iX
Intrinsics Reference Manual.
The characteristics that define the relationship between a
specific asynchronous device and the MPE/iX system are initially
set through system configuration or through the configured terminal
or printer type of the device. When you issue calls to most of the
FCONTROL functions, you are temporarily changing the operating characteristics
of the device on which the file (specified in filenum)
resides.
An exception to this applies to calls to FCONTROL using controlcode
25 through 29. These calls affect only the file specified in the
filenum parameter of the call. They do not
affect the operating characteristics of the device itself or any
other files that might be opened against the same device.
You will generally need to issue several calls to FCONTROL,
each specifying an appropriate controlcode,
to set up the combination of device characteristics that your program
requires. However, for most controlcode values,
you only need to issue one call for a specific characteristic to
be in effect for all files opened against a device. Exceptions to
this include the following.
Controlcode 4 sets a read timeout value
for the next read (timeout value), and controlcode
22 returns the time taken for the last read to your program. Each
of these timer functions, if desired, must be issued for every read.
A number of FCONTROL functions return information to your
program. Some only return information, while others set a new value
and return the old value. You can then use the value returned as
input to a call which resets the device to its previous setting
when your program ends.
Parameters |
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- filenum
16-bit signed integer by value (required)
Contains the file number of the target devicefile as returned
by FOPEN (or HPFOPEN).
- controlcode
16-bit signed integer by value (required)
A code that specifies the control operation to be performed.
The codes used for asynchronous device control are listed below.
With the exception of controlcode = 1, which
sends a carriage control directive to a device, these controls apply
only to terminals.
- 1
Sends a carriage control directive to the device.
- 4
Sets a read timeout value for the next read.
- 10
Changes the line speed of a device. Both input and
output speed are affected.
- 11
Changes the line speed of a device. Both input and
output speed are affected.
- 12
Enables character echoing.
- 13
Disables character echoing.
- 14
Disables the system break function.
- 15
Enables the system break function.
- 16
Disables the subsystem break function.
- 17
Enables the subsystem break function.
- 22
Obtains the time required for the last read to complete.
- 23
Disables parity checking.
- 24
Enables parity checking.
- 25
Defines additional end-of-record (AEOR) character
for terminal input.
- 26
Disables Binary Mode.
- 27
Enables Binary Mode.
- 28
Disables User Block Mode.
- 29
Enables User Block Mode.
- 34
Allows printing of !!!
when the line deletion character is entered.
- 35
Prevents printing of !!!
when the line deletion character is entered.
- 36
Defines parity setting.
- 37
Sets both terminal type and speed.
- 38
Sets terminal type.
- 39
Determines current terminal type.
- 40
Determines current speed setting.
- 41
Enables transparent editing.
- param
type varies passed by reference (required)
The meaning of param depends on the
controlcode being used. However, no matter
what the controlcode is, a value must always
be assigned to param.
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 | NOTE: For a number of the controlcode
functions param has no meaning. In those
cases it must be coded as a dummy parameter, with a value of 0,
because it is a required parameter. |
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The following pages describe each controlcode
value. Each description includes the use of param,
the meaning of condition codes, and any special considerations or
additional discussion.
