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<H1 class="no-header">form_field_validation 3x</H1>
<PRE>
<STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>                            <STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>


</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>form_field_validation</STRONG> - data type validation for fields


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;form.h&gt;</STRONG>

       <STRONG>void</STRONG> <STRONG>*field_arg(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>);</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*field_type(const</STRONG> <STRONG>FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>set_field_type(FIELD</STRONG> <STRONG>*</STRONG><EM>field</EM><STRONG>,</STRONG> <STRONG>FIELDTYPE</STRONG> <STRONG>*</STRONG><EM>type</EM><STRONG>,</STRONG> <STRONG>...);</STRONG>

       /* predefined field types */
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_ALNUM;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_ALPHA;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_ENUM;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_INTEGER;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_NUMERIC;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_REGEXP;</STRONG>
       <STRONG>FIELDTYPE</STRONG> <STRONG>*TYPE_IPV4;</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
       By  default, no validation is done on form fields.  You can associate a
       form with with a <EM>field</EM> <EM>type</EM>, making the form library validate input.


</PRE><H3><a name="h3-field_arg">field_arg</a></H3><PRE>
       Returns a pointer to the field's argument block.  The <EM>argument</EM> <EM>block</EM> is
       an  opaque  structure  containing a copy of the arguments provided in a
       <STRONG>set_field_type</STRONG> call.


</PRE><H3><a name="h3-field_type">field_type</a></H3><PRE>
       Returns a pointer to the <EM>field</EM> <EM>type</EM> associated  with  the  form  field,
       i.e., by calling <STRONG>set_field_type</STRONG>.


</PRE><H3><a name="h3-set_field_type">set_field_type</a></H3><PRE>
       The  function  <STRONG>set_field_type</STRONG> associates a field type with a given form
       field.  This is the type checked by validation functions.   Most  field
       types  are  configurable,  via arguments which the caller provides when
       calling <STRONG>set_field_type</STRONG>.

       Several field types are predefined by the form library.


</PRE><H3><a name="h3-Predefined-types">Predefined types</a></H3><PRE>
       It is possible to set up new  programmer-defined  field  types.   Field
       types  are implemented via the <STRONG>FIELDTYPE</STRONG> data structure, which contains
       several pointers to functions.

       See the <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG> manual page, which describes functions which
       can be used to construct a field-type dynamically.

       The predefined types are as follows:

       TYPE_ALNUM
            Alphanumeric data.  Required parameter:

            <STRONG>o</STRONG>   a third <STRONG>int</STRONG> argument, a minimum field width.

       TYPE_ALPHA
            Character data.  Required parameter:

            <STRONG>o</STRONG>   a third <STRONG>int</STRONG> argument, a minimum field width.

       TYPE_ENUM
            Accept one of a specified set of strings.  Required parameters:

            <STRONG>o</STRONG>   a third <STRONG>(char</STRONG> <STRONG>**)</STRONG> argument pointing to a string list;

            <STRONG>o</STRONG>   a fourth <STRONG>int</STRONG> flag argument to enable case-sensitivity;

            <STRONG>o</STRONG>   a  fifth  <STRONG>int</STRONG> flag argument specifying whether a partial match
                must be a unique one.  If this flag is off, a  prefix  matches
                the  first of any set of more than one list elements with that
                prefix.

            The library copies the string list, so you may  use  a  list  that
            lives in automatic variables on the stack.

       TYPE_INTEGER
            Integer  data,  parsable  to  an  integer  by  <STRONG>atoi(3)</STRONG>.   Required
            parameters:

            <STRONG>o</STRONG>   a third <STRONG>int</STRONG> argument controlling the precision,

            <STRONG>o</STRONG>   a fourth <STRONG>long</STRONG> argument constraining minimum value,

            <STRONG>o</STRONG>   a fifth <STRONG>long</STRONG> constraining maximum value.  If the maximum value
                is  less  than  or  equal  to  the minimum value, the range is
                simply ignored.

            On return, the field buffer is formatted according to  the  <STRONG>printf</STRONG>
            format  specification  ".*ld",  where  the  "*" is replaced by the
            precision argument.

            For details of the precision handling see <STRONG>printf(3)</STRONG>.

       TYPE_NUMERIC
            Numeric  data  (may  have   a   decimal-point   part).    Required
            parameters:

            <STRONG>o</STRONG>   a third <STRONG>int</STRONG> argument controlling the precision,

            <STRONG>o</STRONG>   a fourth <STRONG>double</STRONG> argument constraining minimum value,

            <STRONG>o</STRONG>   and a fifth <STRONG>double</STRONG> constraining maximum value.  If your system
                supports locales, the decimal point character must be the  one
                specified  by  your locale.  If the maximum value is less than
                or equal to the minimum value, the range is simply ignored.

            On return, the field buffer is formatted according to  the  <STRONG>printf</STRONG>
            format  specification  ".*f",  where  the  "*"  is replaced by the
            precision argument.

            For details of the precision handling see <STRONG>printf(3)</STRONG>.

       TYPE_REGEXP
            Regular expression data.  Required parameter:

            <STRONG>o</STRONG>   a third argument, a regular expression <STRONG>(char</STRONG> <STRONG>*)</STRONG>  string.   The
                data is valid if the regular expression matches it.

            Regular expressions are in the format of <STRONG>regcomp</STRONG> and <STRONG>regexec</STRONG>.

            The  regular  expression  must match the whole field.  If you have
            for example, an eight character wide field, a  regular  expression
            "^[0-9]*$"  always means that you have to fill all eight positions
            with digits.  If you want to allow fewer digits, you may  use  for
            example  "^[0-9]*  *$" which is good for trailing spaces (up to an
            empty field), or "^ *[0-9]* *$" which  is  good  for  leading  and
            trailing spaces around the digits.

       TYPE_IPV4
            An Internet Protocol Version 4 address.  Required parameter:

            <STRONG>o</STRONG>   none

            The  form  library  checks  whether or not the buffer has the form
            <EM>a.b.c.d</EM>, where <EM>a</EM>, <EM>b</EM>, <EM>c</EM>, and <EM>d</EM> are numbers in the range 0  to  255.
            Trailing  blanks in the buffer are ignored.  The address itself is
            not validated.

            This is an ncurses extension; this field type may not be available
            in other curses implementations.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       The  functions  <STRONG>field_type</STRONG>  and  <STRONG>field_arg</STRONG>  return  <STRONG>NULL</STRONG> on error.  The
       function <STRONG>set_field_type</STRONG> returns one of the following:

       <STRONG>E_OK</STRONG> The routine succeeded.

       <STRONG>E_SYSTEM_ERROR</STRONG>
            System error occurred (see <STRONG>errno(3)</STRONG>).


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="form.3x.html">form(3x)</A></STRONG>, <STRONG><A HREF="form_fieldtype.3x.html">form_fieldtype(3x)</A></STRONG>, <STRONG><A HREF="form_variables.3x.html">form_variables(3x)</A></STRONG>.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       The  header  file  <STRONG>&lt;form.h&gt;</STRONG>  automatically  includes  the  header  file
       <STRONG>&lt;curses.h&gt;</STRONG>.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       These  routines  emulate  the  System  V  forms library.  They were not
       supported on Version 7 or BSD versions.


</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.


                                                     <STRONG><A HREF="form_field_validation.3x.html">form_field_validation(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-field_arg">field_arg</a></li>
<li><a href="#h3-field_type">field_type</a></li>
<li><a href="#h3-set_field_type">set_field_type</a></li>
<li><a href="#h3-Predefined-types">Predefined types</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-AUTHORS">AUTHORS</a></li>
</ul>
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