---
name: "form_variables"
section: "3form"
platform: "linux"
package: "ncurses-doc"
version: "6.5+20250216-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/form_variables/3form"
---

# form\_variables(3form)

form system global variables

## NAME

**TYPE\_ALNUM**, **TYPE\_ALPHA**, **TYPE\_ENUM**, **TYPE\_INTEGER**, **TYPE\_IPV4**, **TYPE\_NUMERIC**, **TYPE\_REGEXP** - form system global variables

## SYNOPSIS

```
#include <form.h>
```

**FIELDTYPE \* TYPE\_ALNUM;** **FIELDTYPE \* TYPE\_ALPHA;** **FIELDTYPE \* TYPE\_ENUM;** **FIELDTYPE \* TYPE\_INTEGER;** **FIELDTYPE \* TYPE\_IPV4;** **FIELDTYPE \* TYPE\_NUMERIC;** **FIELDTYPE \* TYPE\_REGEXP;**

## DESCRIPTION

**These are building blocks for the form library,** **defining fields that can be created using** **the fieldtype(3FORM) functions.** **Each provides functions for field- and character-validation,** **according to the given datatype.**

### TYPE\_ALNUM

**This holds alphanumeric data.**

### TYPE\_ALPHA

**This holds alphabetic data.**

### TYPE\_ENUM

**This holds an enumerated type.**

### TYPE\_INTEGER

**This holds a decimal integer.**

### TYPE\_IPV4

**This holds an IPv4 internet address, e.g., "127.0.0.1".**

### TYPE\_NUMERIC

**This holds a decimal number, with optional sign and decimal point.**

### TYPE\_REGEXP

**This holds a regular expression.**

## PORTABILITY

**The TYPE\_IPV4 variable is an extension not provided by older** **implementations of the form library.**

## SEE ALSO

**form(3FORM)**