<AWT Dev> awt_Robot.c : format string contains '\0' within the string body

Sergey Bylokhov sergey.bylokhov at oracle.com
Fri Jul 19 21:05:52 UTC 2019

Hi, Matthias. 

I think it is unneeded and can be removed. 

----- matthias.baesken at sap.com wrote: 

Hello, is there a special reason to put a '\0' at the end of the “atom_name” - parameter of the XInternAtom call in isXCompositeDisplay ? 

jdk/src/java.desktop/unix/native/libawt_xawt/awt/awt_Robot.c : 

static jboolean isXCompositeDisplay(Display *display, int screenNumber) { 

char NET_WM_CM_Sn[25]; 

snprintf(NET_WM_CM_Sn, sizeof(NET_WM_CM_Sn), "_NET_WM_CM_S%d\0", screenNumber); 

Atom managerSelection = XInternAtom(display, NET_WM_CM_Sn, 0); 

I think on UNIX the snprintf implementations are conforming and zero-terminate ( exception was VS before VS2015 but this is unix/native code ). 

Reason why I ask is this warning we have in our AIX xlc16/xlclang build : 

/jdk/src/java.desktop/unix/native/libawt_xawt/awt/awt_Robot.c:153:65: warning: format string contains '\0' within the string body [-Wformat] 

snprintf(NET_WM_CM_Sn, sizeof(NET_WM_CM_Sn), "_NET_WM_CM_S%d\0", screenNumber); 

Thanks, Matthias
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