Atom-management functions create and manipulate atoms. Atoms are integers that uniquely identify character strings. They are useful in applications that use many character strings and in applications that need to conserve memory. Windows stores atoms in atom tables. A local atom table is allocated in an application's data segment; it cannot be accessed by other applications. The global atom table can be shared and is useful in applications that use dynamic data exchange (DDE). Following are the atom-management functions:
| Function | Description |
| AddAtom | Creates an atom for a character string. |
| DeleteAtom | Deletes an atom if the reference count is zero. |
| FindAtom | Retrieves an atom associated with a character string. |
| GetAtomHandle | Retrieves a handle (relative to the local heap) of the string that corresponds to a specified atom. |
| GetAtomName | Copies the character string associated with an atom. |
| GlobalAddAtom | Creates a global atom for a character string. |
| GlobalDeleteAtom | Deletes a global atom if the reference count is zero. |
| GlobalFindAtom | Retrieves a global atom associated with a character string. |
| GlobalGetAtomName | Copies the character string associated with a global atom. |
| InitAtomTable | Initializes an atom hash table. |
The MAKEINTATOM macro can also be used to cast an integer for use as a function argument.