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31 .\" $Id: form_driver.3x,v 1.59 2024/03/16 15:35:01 tom Exp $
32 .TH form_driver 3X 2024-03-16 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
39 \fBform_driver_w\fP \-
40 command-processing loop of the form system
45 \fBint form_driver(FORM *\fIform\fP, int \fIc\fP);
46 \fBint form_driver_w(FORM *\fIform\fP, int \fIc\fP, wchar_t \fIwch\fP);
50 Once a form has been posted (displayed), you should funnel input events to it
51 through \fBform_driver\fP. This routine has three major input cases:
53 The input is a form navigation request.
54 Navigation request codes are constants defined in \fB<form.h>\fP,
55 which are distinct from the key- and character codes returned
58 The input is a printable character.
59 Printable characters (which must be positive, less than 256) are
60 checked according to the program's locale settings.
62 The input is the KEY_MOUSE special key associated with an mouse event.
64 This extension simplifies the use of the forms library using wide characters.
65 The input is either a key code (a request) or a wide character
66 returned by \fBget_wch\fP(3X).
67 The type must be passed as well,
68 to enable the library to determine whether the parameter
69 is a wide character or a request.
70 .SS "Form Driver Requests"
71 The form driver requests are as follows:
78 REQ_BEG_FIELD Move to beginning of field.
79 REQ_BEG_LINE Move to beginning of the line.
80 REQ_CLR_EOF Clear to end of field from cursor.
81 REQ_CLR_EOL Clear to end of line from cursor.
82 REQ_CLR_FIELD Clear the entire field.
83 REQ_DEL_CHAR Delete character at the cursor.
84 REQ_DEL_LINE Delete line at the cursor.
85 REQ_DEL_PREV Delete character before the cursor.
86 REQ_DEL_WORD Delete blank-delimited word at cursor.
87 REQ_DOWN_CHAR Move down in field.
88 REQ_DOWN_FIELD Move down to a field.
89 REQ_END_FIELD Move to the end of field.
90 REQ_END_LINE Move to the end of the line.
91 REQ_FIRST_FIELD Move to the first field.
92 REQ_FIRST_PAGE Move to the first page.
93 REQ_INS_CHAR Insert a blank at the cursor.
94 REQ_INS_LINE Insert a blank line at the cursor.
95 REQ_INS_MODE Enter insert mode.
96 REQ_LAST_FIELD Move to the last field.
97 REQ_LAST_PAGE Move to the last field.
98 REQ_LEFT_CHAR Move left in field.
99 REQ_LEFT_FIELD Move left to a field.
100 REQ_NEW_LINE Insert or overlay a new line.
101 REQ_NEXT_CHAR Move to the next char.
102 REQ_NEXT_CHOICE Display next field choice.
103 REQ_NEXT_FIELD Move to the next field.
104 REQ_NEXT_LINE Move to the next line.
105 REQ_NEXT_PAGE Move to the next page.
106 REQ_NEXT_PAGE Move to the next page.
107 REQ_NEXT_WORD Move to the next word.
108 REQ_OVL_MODE Enter overlay mode.
109 REQ_PREV_CHAR Move to the previous char.
110 REQ_PREV_CHOICE Display previous field choice.
111 REQ_PREV_FIELD Move to the previous field.
112 REQ_PREV_LINE Move to the previous line.
113 REQ_PREV_PAGE Move to the previous page.
114 REQ_PREV_WORD Move to the previous word.
115 REQ_RIGHT_CHAR Move right in field.
116 REQ_RIGHT_FIELD Move right to a field.
117 REQ_SCR_BCHAR Scroll field backward 1 character.
118 REQ_SCR_BHPAGE Scroll field backward \(12 page.
119 REQ_SCR_BLINE Scroll field backward 1 line.
120 REQ_SCR_BPAGE Scroll field backward 1 page.
121 REQ_SCR_FCHAR Scroll field forward 1 character.
122 REQ_SCR_FHPAGE Scroll field forward \(12 page.
123 REQ_SCR_FLINE Scroll field forward 1 line.
124 REQ_SCR_FPAGE Scroll field forward 1 page.
125 REQ_SCR_HBHALF Horizontal scroll field backward \(12 line.
126 REQ_SCR_HBLINE Horizontal scroll field backward 1 line.
127 REQ_SCR_HFHALF Horizontal scroll field forward \(12 line.
128 REQ_SCR_HFLINE Horizontal scroll field forward 1 line.
129 REQ_SFIRST_FIELD Move to the sorted first field.
130 REQ_SLAST_FIELD Move to the sorted last field.
131 REQ_SNEXT_FIELD Move to the sorted next field.
132 REQ_SPREV_FIELD Move to the sorted previous field.
133 REQ_UP_CHAR Move up in field.
134 REQ_UP_FIELD Move up to a field.
135 REQ_VALIDATION Validate field.
138 If the second argument is a printable character, the driver places it
139 in the current position in the current field.
140 If it is one of the forms
141 requests listed above, that request is executed.
142 .SS "Field Validation"
143 The form library makes updates to the window associated
144 with form fields rather than directly to the field buffers.
146 The form driver provides low-level control over updates to the form fields.
147 The form driver also provides for validating modified fields
148 to ensure that the contents
149 meet whatever constraints an application may attach using \fBset_field_type\fP.
151 You can validate a field without making any changes to it using
152 \fBREQ_VALIDATION\fP.
153 The form driver also validates a field in these cases:
155 a call to \fBset_current_field\fP attempts to move to a different field.
157 a call to \fBset_current_page\fP attempts to move
158 to a different page of the form.
160 a request attempts to move to a different field.
162 a request attempts to move to a different page of the form.
164 In each case, the move fails if the field is invalid.
166 If the modified field is valid, the form driver copies the modified
167 data from the window associated with the field
170 If the second argument is the KEY_MOUSE special key, the associated
171 mouse event is translated into one of the above pre-defined requests.
172 Currently only clicks in the user window (e.g., inside the form display
173 area or the decoration window) are handled.
175 If you click above the display region of the form:
178 a REQ_PREV_FIELD is generated for a single click,
180 a REQ_PREV_PAGE is generated for a double-click and
182 a REQ_FIRST_FIELD is generated for a triple-click.
185 If you click below the display region of the form:
188 a REQ_NEXT_FIELD is generated for a single click,
190 a REQ_NEXT_PAGE is generated for a double-click and
192 a REQ_LAST_FIELD is generated for a triple-click.
195 If you click at an field inside the display area of the form:
198 the form cursor is positioned to that field.
200 If you double-click a field,
201 the form cursor is positioned to that field
202 and \fBE_UNKNOWN_COMMAND\fP is returned.
203 This return value makes sense,
204 because a double click usually means that an field-specific action should
206 It is exactly the purpose of this return value to signal that an
207 application specific command should be executed.
210 into a request was done, \fBform_driver\fP returns the result of this request.
213 If you clicked outside the user window
214 or the mouse event could not be translated
215 into a form request an \fBE_REQUEST_DENIED\fP is returned.
216 .SS "Application-defined Commands"
217 If the second argument is neither printable nor one of the above
218 pre-defined form requests, the driver assumes it is an application-specific
219 command and returns \fBE_UNKNOWN_COMMAND\fP. Application-defined commands
220 should be defined relative to \fBMAX_COMMAND\fP, the maximum value of these
221 pre-defined requests.
223 \fBform_driver\fP returns one of the following error codes:
226 The routine succeeded.
229 Routine detected an incorrect or out-of-range argument.
232 Routine was called from an initialization or termination function.
235 The form has not been posted.
238 Contents of field is invalid.
241 No fields are connected to the form.
244 The form driver could not process the request.
247 System error occurred (see \fBerrno\fP(3)).
250 The form driver code saw an unknown request code.
252 These routines emulate the System V forms library.
253 They were not supported on
254 Version 7 or BSD versions.
257 Manual pages and adaptation for new curses by Eric S. Raymond.
261 \fB\%form_fieldtype\fP(3X),
262 \fB\%form_field_buffer\fP(3X),
263 \fB\%form_field_validation\fP(3X),
264 \fB\%form_variables\fP(3X),