User manual

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mikroC PRO for PIC32

MikroElektronika

217

Anonymous Unions

Anonymous unions are unions that are declared without tag or declarator:

union { member-declarator-list };

Such union declarations do not declare types; they declare an unnamed objects.

The name of each union member must be unique within the scope where the union is declared.

In C, an anonymous union can have a tag; it cannot have declarators. Names declared in an anonymous union are

used directly, like nonmember variables.

In addition to the restrictions listed above in Union, anonymous unions are subject to additional restrictions:

- They must also be declared as static if declared in global scope. If declared in local scope, they must be

either static or automatic, not external

- They can have only public members; private and protected members in anonymous unions generate

errors.

- They cannot have function members.

Here is a simple example:

union { // no union tag

int i;

oat f;

union { // no union tag

unsigned char uc;

char c;

}; // no declarator

Anonymous Union Member Access

Anonymous union members are accessed directly because they are in the scope containing the anonymous union:

// Referring to declarations from the example above:

i = 1;

f = 3.14;

uc = ‘c’;

c = ‘u’;