libxrdeveloper's documentation
void xr_call_set_error ( xr_call call,
int  code,
const char *  msg,
  ... 
)

Set retval to be stadard XML-RPC error structure.

If error is set and retval is set too, error gets preference on serialize response.

Parameters:
call Call obejct.
code Error code.
msg Error message.
Documentation for libxr, Sun Nov 28 2010 22:37:18.