Can applications runs in domainU use grant table?

I found a way in the document(/docs/misc/grant-tables.txt), using function gnttab_grant_foreign_access . But, this fucntion is defined in domainU kernel, for example, in my installation, it's in /linux-2.6.18-xen.hg/include/xen/gnttab.h. 

Then how can I call this function in my own application? 
If I wants to write a simple program(program1) runs in domainA, to map a frame to domainB, in which another simple program(program2) is running, then program2 can read the information program1 sent to domainB, what should I do?

thanks.

2011-04-04 



Wishes
Ruozeng W