thank you you all! now i understand the reason and solution.
2010/6/10 Daniel Stone <[email protected]> > > On Thu, Jun 10, 2010 at 03:10:52PM +0800, xin zhang wrote: > > Hi experts: > > In Xvfb implementation, the frame buffer is allocated with IPC_PRIVATE > > if uses SHM. > > Given that IPC_PRIVATE is just useful to parent/child process, and given > > X is a single process, > > I don't realize what is the use. > > Why not add a param which allows user pass a string to produce IPC key, > > and create share memory > > with the key, then other process will really access to the frame buffer. > > I think this will benefit many softwares, e.g. VNC, there is no need to > > write an individual X server, just > > do an extension hooks on Xvfb is OK. > > > > Does anyone know the reason? is it for security? thank you. > > Because direct access to the framebuffer might get you anything, > including corruption if you access it in the middle of a copy. If you > want to get the framebuffer contents through SHM, use XShmGetImage(). > > Cheers, > Daniel > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.10 (GNU/Linux) > > iEYEARECAAYFAkwQx+sACgkQUVYB1rKAgJSlWACcDxZSx3jw2qBAQbFvk2CkucYp > GVEAoKe/Qt/59aHMY8gI77pD8g4udy+j > =+GMl > -----END PGP SIGNATURE----- > _______________________________________________ [email protected]: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
