- The function new_fieldtype creates a new field type usable
- for data validation. You supply it with field_check, a
- predicate to check the validity of an entered data string
- whenever the user attempts to leave a field. The (FIELD
- *) argument is passed in so the validation predicate can
- see the field's buffer, sizes and other attributes; the
- second argument is an argument-block structure, about
- which more below.
-
- You also supply new_fieldtype with char_check, a function
- to validate input characters as they are entered; it will
- be passed the character to be checked and a pointer to an
- argument-block structure.
-
- The function free_fieldtype frees the space allocated for
- a given validation type.
-
- The function set_fieldtype_arg associates three storage-
- management functions with a field type. The make_arg
- function is automatically applied to the list of arguments
- you give set_field_type when attaching validation to a
- field; its job is to bundle these into an allocated argu-
- ment-block object which can later be passed to validation
- predicated. The other two hook arguments should copy and
- free argument-block structures. They will be used by the
- forms-driver code. You must supply the make_arg function,
- the other two are optional, you may supply NULL for them.
- In this case it is assumed that make_arg does not allocate
- memory but simply loads the argument into a single scalar
- value.
-
- The function link_fieldtype creates a new field type from
- the two given types. They are connected by an logical
- 'OR'.
-
- The form driver requests REQ_NEXT_CHOICE and
- REQ_PREV_CHOICE assume that the possible values of a field
- form an ordered set, and provide the forms user with a way
- to move through the set. The set_fieldtype_choice func-
- tion allows forms programmers to define successor and pre-
- decessor functions for the field type. These functions
- take the field pointer and an argument-block structure as
+ intset_fieldtype_arg(
+ FIELDTYPE*fieldtype,
+ void*(*constmake_arg)(va_list*),
+ void*(*constcopy_arg)(constvoid*),
+ void(*constfree_arg)(void*));
+ intset_fieldtype_choice(
+ FIELDTYPE*fieldtype,
+ bool(*constnext_choice)(FIELD*,constvoid*),
+ bool(*constprev_choice)(FIELD*,constvoid*));
+
+ FIELDTYPE*link_fieldtype(FIELDTYPE*type1,
+ FIELDTYPE*type2);
+
+
+
+ The function new_fieldtype creates a new field type usable for data
+ validation. Its parameters are function pointers:
+
+ field_check
+ This function checks the validity of an entered data string
+ whenever the user attempts to leave a field. It has two
+ arguments:
+
+ o The (FIELD *) argument is passed in so the validation
+ predicate can see the field's buffer, sizes and other
+ attributes.
+
+ o The second argument is an argument-block structure, about
+ which more below.
+
+ char_check
+ This function validates input characters as they are entered. The
+ form library passes it the character to be checked and a pointer
+ to an argument-block structure.
+
+
+
+ The function set_fieldtype_arg associates three storage-management
+ functions with a field type:
+
+ make_arg
+ This function is automatically applied to the list of arguments
+ you give set_field_type when attaching validation to a field. It
+ stores the arguments in an allocated argument-block object which
+ is used when validating input.
+
+ copy_arg
+ This function may be used by applications to copy argument-blocks.
+
+ free_arg
+ Frees an argument-block structure.
+
+ You must supply the make_arg function. The other two are optional: you
+ may supply NULL for them. In this case, the form library assumes that
+ make_arg does not allocate memory but simply loads the argument into a
+ single scalar value.
+
+
+
+ The form driver requests REQ_NEXT_CHOICE and REQ_PREV_CHOICE assume
+ that the possible values of a field form an ordered set, and provide
+ the forms user with a way to move through the set.
+
+ The set_fieldtype_choice function allows forms programmers to define
+ successor and predecessor functions for the field type. These
+ functions take the field pointer and an argument-block structure as
arguments.
-
+ The pointer-valued routines return NULL on error. They set errno
+ according to their success:
E_OK The routine succeeded.
E_BAD_ARGUMENT
- Routine detected an incorrect or out-of-range argu-
- ment.
+ Routine detected an incorrect or out-of-range argument.
E_SYSTEM_ERROR
System error occurred, e.g., malloc failure.
- The integer-valued routines return one of the following
- codes on error:
+ The integer-valued routines return one of the following codes on error:
E_OK The routine succeeded.
E_BAD_ARGUMENT
- Routine detected an incorrect or out-of-range argu-
- ment.
+ Routine detected an incorrect or out-of-range argument.
E_CONNECTED
The field is already connected to a form.
@@ -149,44 +166,44 @@
The field is the current field.
E_SYSTEM_ERROR
- System error occurred (see errno).
-
+ System error occurred (see errno(3)).
-
- The header file <form.h> automatically includes the header
- file <curses.h>.
- All of the (char*) arguments of these functions should
- actually be (void*). The type has been left uncorrected
- for strict compatibility with System V.
+