NAME

ESCAPE -3 − disable or enable PHIGS DC bounds checking

SYNOPSIS

C Syntax

void
pescape ( func_id, in, store, out )
Pintfunc_id;escape function identifier
Pescape_in_data∗in; input data for the function
Pstorestore;not used
Pescape_out_data∗∗out; OUT not used

Required PHIGS Operating States

(PHOP, ∗, ∗, ∗)

DESCRIPTION

Purpose

ESCAPE -3 disables or enables Device Coordinate (DC) bounds checking by PHIGS functions with DC input parameters (such as SET WORKSTATION VIEWPORT and the input device initialization functions). 

C Input Parameters

func_id
The function identifier for this escape is PUESC_IGNORE_DC_ERRORS, which is defined in phigs.h to be -3. 

inA pointer to a Pescape_in_data union, which contains the escape_in_u3 member used by this escape function.  This member is defined in phigs.h as:

struct {
Pintignore_DC_errors; /∗ ignore errors if non-zero ∗/
} escape_in_u3;

ignore_DC_errors indicates if DC bounds checking is enabled (0, the default) or disabled (non-zero). 

storeNot used. 

C Output Parameters

outThere is no output data record for this escape. 

Execution

This escape disables or enables bounds checking of DC parameters specifed to PHIGS functions.  A number of PHIGS workstation functions have DC values as parameters.  Normally these values are checked against the current DC size of the workstation when the function is called, and an error is reported if any of the values lie outside the current limits.  The function then returns without performing the desired operation.  This escape is used to override that behavior by indicating that DC values outside the current workstation limits should be accepted.  This allows such DC values to be entered into the workstation state list and used in subsequent PHIGS operations.  The use of these values in not defined by the PHIGS standard, but PHIGS will use them as it would values that are within range.  This may produce results that do not conform to the PHIGS standard.  It is the application’s responsibility to ensure that the results of PHIGS’ use of these out-of-range values is meaningful. 

ERRORS

003Ignoring function, function requires state (PHOP, WSOP, ∗, ∗)

SEE ALSO

ESCAPE (3P)

September 02, 1992