- 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
+
+ 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 predi-
+ cate 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 vali-
+ dation 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
+ argument-block object which can later be passed to validation predi-
+ cated. 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 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
- arguments.
+ 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_field-
+ type_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.
-
-
RETURN VALUE
- The pointer-valued routines return NULL on error. They
- set errno according to their success:
+
+ 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.
@@ -148,43 +133,46 @@
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.
+ All of the (char*) arguments of these functions should actually be
+ (void*). The type has been left uncorrected for strict compatibility
+ with System V.
-
-
PORTABILITY
- These routines emulate the System V forms library. They
- were not supported on Version 7 or BSD versions.
+