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free_fieldtype (3)
  • >> free_fieldtype (3) ( FreeBSD man: Библиотечные вызовы )
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    NAME

    form_fieldtype - define validation-field types
     
    

    SYNOPSIS

    #include <form.h>
    FIELDTYPE *new_fieldtype(
        bool (* const field_check)(FIELD *, const void *),
        bool (* const char_check)(int, const void *));
    int free_fieldtype(FIELDTYPE *fieldtype);
    int set_fieldtype_arg(
        FIELDTYPE *fieldtype,
        void *(* const make_arg)(va_list *),
        void *(* const copy_arg)(const void *),
        void  (* const free_arg)(void *));
    int set_fieldtype_choice(
        FIELDTYPE *fieldtype,
        bool (* const next_choice)(FIELD *, const void *),
        bool (* const prev_choice)(FIELD *, const void *));
    FIELDTYPE *link_fieldtype(FIELDTYPE *type1,
                              FIELDTYPE *type2);
     

    DESCRIPTION

    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 argument-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 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:
    E_OK
    The routine succeeded.
    E_BAD_ARGUMENT
    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:

    E_OK
    The routine succeeded.
    E_BAD_ARGUMENT
    Routine detected an incorrect or out-of-range argument.
    E_CONNECTED
    The field is already connected to a form.
    E_CURRENT
    The field is the current field.
    E_SYSTEM_ERROR
    System error occurred (see errno).
     

    SEE ALSO

    curses(3X), form(3X).  

    NOTES

    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.  

    PORTABILITY

    These routines emulate the System V forms library. They were not supported on Version 7 or BSD versions.  

    AUTHORS

    Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S. Raymond.


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    RETURN VALUE
    SEE ALSO
    NOTES
    PORTABILITY
    AUTHORS


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