BM_GETCHECK
wParam = 0; /* not used, must be zero */
lParam = 0L; /* not used, must be zero */An application sends a BM_GETCHECK message to retrieve the check state of a button.
This message has no parameters.
The return value from a button created with the BS_AUTOCHECKBOX, BS_AUTORADIOBUTTON, BS_AUTO3STATE, BS_CHECKBOX, BS_RADIOBUTTON, or BS_3STATE style may be one of the following values:
| Value | Meaning |
| 0 | Button state is unchecked. |
| 1 | Button state is checked. |
| 2 | Button state is indeterminate (applies only if the button has the BS_3STATE or BS_AUTO3STATE style). |
If the button has any other style, the return value is 0.
This example determines if the ID_MYCHECKBOX control is currently checked:
int checked;
checked = (int) SendDlgItemMessage(hwndDlg, ID_MYCHECKBOX,
BM_GETCHECK, 0, 0L);