#pragma enum

Purpose

Specifies the amount of storage occupied by enumerations.

Syntax


                       .-small---.      
>>-#--pragma--enum--(--+-int-----+--)--------------------------><
                       +-1-------+      
                       +-2-------+      
                       +-4-------+      
                       +-8-------+      
                       +-intlong-+      
                       +-reset---+      
                       '-pop-----'

Defaults

The default is small.

Parameters

small

Specifies that an enumeration occupies the minimum amount of storage required by the smallest predefined type that can represent that range of enumeration constants: either 1, 2, or 4 bytes of storage. If the specified storage size is smaller than that required by the range of the enumeration constants, the compiler issues a diagnostic message. For example:

#pragma enum(1)
enum e_tag {
   a=0,
   b=SHRT_MAX  /* diagnostic message */
} e_var;
#pragma enum(reset)

int

Specifies that an enumeration occupies 4 bytes of storage and is represented by int.

1

Specifies that an enumeration occupies 1 byte of storage.

2

Specifies that an enumeration occupies 2 bytes of storage.

4

Specifies that an enumeration occupies 4 bytes of storage.

8

Specifies that an enumeration occupies 8 bytes of storage. This suboption is only valid with LP64.

intlong

Specifies that an enumeration occupies 8 bytes of storage and is represented as a long if the range of the enumeration constants exceeds the limit for type int. Otherwise, enumerations occupy 4 bytes of storage and are of type int. This suboption is only valid with LP64. C++ only.

reset

pop

Sets the enum setting to that which was in effect before the current setting.

Usage

The directive is in effect until the next valid #pragma enum directive is encountered. For every #pragma enum directive in your program, it is good practice to have a corresponding #pragma enum(reset) or #pragma enum(pop) as well. This is the only way to prevent one file from potentially changing the enum setting of another file that is included.

You cannot have #pragma enum directives within the declaration of an enumeration. The following code segment generates a warning message and the second occurrence of the pragma is ignored:

#pragma enum(small)
enum e_tag {
     a,
     b,
#pragma enum(int) /*cannot be within a declaration */
     c
} e_var;

Related information

For detailed information on the preferred sign and type for each range of enumeration constants, see the description of the ENUMSIZE compiler option in the z/OS® XL C/C++ User's Guide.