Check if a textbox control is empty C++ Win32

i have this code that put the value of a textbox field in the variable. The textbox is a Ip Address Control. How can i check if when the user press the OK button the field is empty or not? Thank you

char *myVar = new char[16];
*myVar = NULL;

GetDlgItemTextA(hDlg, IDC_MYVAR, myVar开发者_如何学Python, 16);

delete [] myVar;

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You probably have to use the IPM_ISBLANK message (i am not an expert on winapi, so i may be mistaken).

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I'd just get hold of the HWND for the control, send it a WM_GETTEXTLENGTH and compare the answer with zero.

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Just check whether myVar[0] is zero after calling GetDlgItemTextA.

char myVar[16];
GetDlgItemTextA(hDlg, IDC_MYVAR, myVar, 16);
if (myVar[0] == 0) // then field is empty

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See here: GetWindowText Function