Additional Topics > External Development Guide > IDLInternals - Miscellaneous > Type Information

# Type Information

The following read-only global variables provide information about IDL data.

Note: Under Windows, these global variables are not available; use the functions listed below to retrieve the values contained in the global variables.

### IDL_OutputFormat

An array of pointers to character strings. IDL_OutputFormat is indexed by type code, and specifies the default output formats for the different data types (see Type Codes). The default formats are used by the PRINT and STRING built- in routines as well as for type conversions.

### IDL_OutputFormatLen

An array of integers. IDL_OutputFormatLen gives the length in characters of the corresponding elements of IDL_OutputFormat.

### IDL_TypeSize

An array of long integers. IDL_TypeSize is indexed by type code, and gives the size of the data object used to represent each type.

### IDL_TypeName

An array of pointers to character strings. IDL_TypeName is indexed by type code, and gives a descriptive string for each type.

## Functions for Returning Data Type Variable Values

The following functions can be used to return the values contained in the global variables described above, but in a functional form.

### char *IDL_OutputFormatFunc(int type)

Given an IDL type code, this function returns the default output format for that type. This is equivalent to accessing the IDL_OutputFormat array.

### int IDL_OutputFormatLenFunc(int type)

Given an IDL type code, this function returns the default output format length for that type. This is equivalent to accessing the IDL_OutputFormatLen array.

### int IDL_TypeSizeFunc(int type)

Given an IDL type code, this function returns the size of the data object used to represent that type. This is equivalent to accessing the IDL_TypeSize array.

### char *IDL_TypeNameFunc(int type)

Given an IDL type code, this function returns the name of the type as a null terminated character string. This is equivalent to accessing the IDL_TypeName array.