warning                 package:base                 R Documentation

_W_a_r_n_i_n_g _M_e_s_s_a_g_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     Generates a warning message that corresponds to its argument(s)
     and (optionally) the expression or function from which it was
     called.

_U_s_a_g_e:

     warning(..., call. = TRUE)

_A_r_g_u_m_e_n_t_s:

     ...: character vectors (which are pasted together with no
          separator) or `NULL'.

   call.: logical, indicating if the call should become part of the
          warning message.

_D_e_t_a_i_l_s:

     The result depends on the value of `options("warn")'.

     If `warn' is negative warnings are ignored; if it is zero they are
     stored and printed after the top-level function has completed; if
     it is one they are printed as they occur and if it is 2 (or
     larger) warnings are turned into errors.

     If `warn' is zero (the default), a top-level variable
     `last.warning' is created.  It contains the warnings which can be
     printed via a call to `warnings'.

_S_e_e _A_l_s_o:

     `stop' for fatal errors, `warnings', and `options' with argument
     `warn='.

_E_x_a_m_p_l_e_s:

     testit <- function() warning("testit")
     testit() ## shows call
     testit <- function() warning("problem in testit", call. = FALSE)
     testit() ## no call

