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.\" $XConsortium: p256,v 5.3 94/04/17 20:57:24 hersh Exp $
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$XMCOPY
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.ds b \s-2BREAK\s+2
.TH "REQUEST STRING" 3P "29 February 1991"
.SH NAME
REQUEST STRING \- request an operator interaction with a string device
.IX "String Input Devices" "REQUEST STRING"
.IX "Request Input Mode" "REQUEST STRING"
.IX "Input Modes" "REQUEST STRING"
.SH SYNOPSIS
.SS C Syntax
.ft B
.ta 1.25i 3i
.nf
void
preq_string ( ws, dev, in_status, string )
Pint	ws;	\fIworkstation identifier\fP
Pint	dev;	\fIstring device number\fP
Pin_status	*in_status;	\fI\s-2OUT\s+2 input string\fP
char	*string;	\fI\s-2OUT\s+2 string\fP
.fi
.ft R
.SS Required PHIGS Operating States
(PHOP, WSOP, *, *)
.SH DESCRIPTION
.SS Purpose
Use \s-2REQUEST STRING\s+2 to request an operator interaction with a
specified string device. The device must be in request mode. See
\s-2SET STRING MODE\s+2 and \s-2INITIALIZE STRING\s+2 for more information.
See the \fIAvailable Devices\fP section of \s-2INITIALIZE STRING\s+2 for a
description of the available string devices.
.LP
The request suspends \s-2PHIGS\s+2 until the specified device is triggered
or the operator performs a \*b.
A \*b is performed by typing the \s-2CONTROL\s+2 and \s-2D\s+2 keys
simultaneously (^D).
.SS C Input Parameters
.IP \fIws\fP
Workstation identifier. An integer specifying the workstation with which
the requested string device is associated.
.IP \fIdev\fP
The device number of the requested string device.
See the \fIAvailable Devices\fP section of \s-2INITIALIZE STRING\s+2 for a
description of the available string devices.
.SS C Output Parameter
.IP \fIin_status\fP
A pointer to the location to store the status of the request.
Pin_status is defined in phigs.h as follows:
.sp .4
.ta .5i
.nf
typedef enum {
.sp .2
	PIN_STATUS_NONE,
	PIN_STATUS_OK,
	PIN_STATUS_NO_IN
.sp .2
} Pin_status;
.fi
.IP \fIstring\fP
A pointer to an array in which to store the string.
The array must be allocated by the caller and should be at least as large
as the buffer size of the device.
.SS Execution
\s-2REQUEST STRING\s+2 requests a logical input value from the specified
string device. The specified device must be in request mode. See
\s-2SET STRING MODE\s+2 for more information.
.LP
\s-2REQUEST STRING\s+2 creates a measure
process for the specified device and suspends \s-2PHIGS\s+2 until the
device is triggered or the operator issues a \*b. 
A \*b is generated by the operator by depressing the
\s-2CONTROL\s+2 and \s-2D\s+2 keys
simultaneously (^D).
.LP
If a \*b occurs, a status of \s-2PIN_STATUS_NO_IN\s+2 is
returned and the string data is undefined. 
If a status of \s-2PIN_STATUS_OK\s+2 is returned,
the string data is available. 
In either case, the measure process is terminated and
\s-2PHIGS\s+2 processing resumes.
.LP
For a description of the available string devices, see \s-2INITIALIZE STRING\s0.
.SH ERRORS
.IP 003
Ignoring function, function requires state 
(\s-2PHOP\s+2, \s-2WSOP\s+2, \s-2*\s+2, \s-2*\s+2)
.IP 054
Ignoring function, the specified workstation is not open
.IP 061
Ignoring function, specified workstation is neither of category \s-2INPUT\s+2
nor of category \s-2OUTIN\s+2
.IP 250
Ignoring function, the specified device is not available
on the specified workstation
.IP 251
Ignoring function, the function requires the input
device to be in \s-2REQUEST\s+2 mode
.SH SEE ALSO
.nf
.IP
.ta 0.5i
.SM "INITIALIZE STRING (3P)"
.SM "SET STRING MODE (3P)"
.fi
