libxrdeveloper's documentation
#define xr_debug (   mask,
  fmt,
  args... 
)    do { if (G_UNLIKELY(xr_debug_enabled & mask)) _xr_debug(G_STRLOC ": ", fmt, ## args); } while(0)

Conditional debug message.

Parameters:
mask XR_DEBUG_* constant that enables this message.
fmt Message format (printf like).
args Variable arguments.
Documentation for libxr, Mon Nov 29 2010 06:10:59.