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

Baesken, Matthias matthias.baesken at sap.com
Fri Jul 19 12:01:51 UTC 2019

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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