- The function set_field_type declares a data type for a given form
- field. This is the type checked by validation functions. The prede-
- fined types are as follows:
+ By default, no validation is done on form fields. You can associate a
+ form with with a fieldtype, making the form library validate input.
+
+
+
+ Returns a pointer to the field's argument block. The argumentblock is
+ an opaque structure containing a copy of the arguments provided in a
+ set_field_type call.
+
+
+
+ The function set_field_type 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 set_field_type.
+
+ Several field types are predefined by the form library.
+
+
+
+ It is possible to set up new programmer-defined field types. Field
+ types are implemented via the FIELDTYPE data structure, which contains
+ several pointers to functions.
+
+ See the form_fieldtype(3x) 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. Requires a third int argument, a minimum field
- width.
+ Alphanumeric data. Required parameter:
+
+ o a third int argument, a minimum field width.
TYPE_ALPHA
- Character data. Requires a third int argument, a minimum field
- width.
+ Character data. Required parameter:
+
+ o a third int argument, a minimum field width.
TYPE_ENUM
- Accept one of a specified set of strings. Requires a third (char
- **) argument pointing to a string list; a fourth int flag argument
- to enable case-sensitivity; and a fifth int flag argument specify-
- ing 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). Please notice that the string list is
- copied. So you may use a list that lives in automatic variables on
- the stack.
+ Accept one of a specified set of strings. Required parameters:
+
+ o a third (char**) argument pointing to a string list;
+
+ o a fourth int flag argument to enable case-sensitivity;
+
+ o a fifth int 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 atoi(3). Requires a third
- int argument controlling the precision, a fourth long argument
- constraining minimum value, and a fifth long 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 printf format specification ".*ld",
- where the '*' is replaced by the precision argument. For details
- of the precision handling see printf's man-page.
+ Integer data, parsable to an integer by atoi(3). Required
+ parameters:
+
+ o a third int argument controlling the precision,
+
+ o a fourth long argument constraining minimum value,
+
+ o a fifth long 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 printf
+ format specification ".*ld", where the "*" is replaced by the
+ precision argument.
+
+ For details of the precision handling see printf(3).
TYPE_NUMERIC
- Numeric data (may have a decimal-point part). Requires a third int
- argument controlling the precision, a fourth double argument con-
- straining minimum value, and a fifth double constraining maximum
- value. If your system supports locales, the decimal point charac-
- ter to be used 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 printf format specification ".*f", where the '*'
- is replaced by the precision argument. For details of the preci-
- sion handling see printf's man-page.
+ Numeric data (may have a decimal-point part). Required
+ parameters:
+
+ o a third int argument controlling the precision,
+
+ o a fourth double argument constraining minimum value,
+
+ o and a fifth double 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 printf
+ format specification ".*f", where the "*" is replaced by the
+ precision argument.
+
+ For details of the precision handling see printf(3).
TYPE_REGEXP
- Regular expression data. Requires a regular expression (char*)
- third argument; the data is valid if the regular expression
- matches it. Regular expressions are in the format of regcomp and
- regexec. Please notice that 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]* *$"
- which is good for leading and trailing spaces around the digits.
+ Regular expression data. Required parameter:
+
+ o a third argument, a regular expression (char*) string. The
+ data is valid if the regular expression matches it.
+
+ Regular expressions are in the format of regcomp and regexec.
+
+ The regular expression must match the whole field. If you have
+ for example, an eight character wide field, a regular expression
+ "^[0-9]*$" 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. This requires no addi-
- tional argument. It is checked whether or not the buffer has the
- form a.b.c.d, where a,b,c and d are numbers between 0 and 255.
- Trailing blanks in the buffer are ignored. The address itself is
- not validated. Please note that this is an ncurses extension. This
- field type may not be available in other curses implementations.
+ An Internet Protocol Version 4 address. Required parameter:
- It is possible to set up new programmer-defined field types. See the
- form_fieldtype(3x) manual page.
+ o none
+
+ The form library checks whether or not the buffer has the form
+ a.b.c.d, where a, b, c, and d 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.
- The functions field_type and field_arg return NULL on error. The func-
- tion set_field_type returns one of the following:
+ The functions field_type and field_arg return NULL on error. The
+ function set_field_type returns one of the following:
E_OK The routine succeeded.
E_SYSTEM_ERROR
- System error occurred (see errno).
+ System error occurred (see errno(3)).
- These routines emulate the System V forms library. They were not sup-
- ported on Version 7 or BSD versions.
+ These routines emulate the System V forms library. They were not
+ supported on Version 7 or BSD versions.