Ncurses no-wrap mode when adding strings to window

Question

I'm adding strings to a window, with waddwstr() function, one line after other, in consecutive rows. I don't want ncurses to automatically wrap lines for me – I'm overwriting them with consecutive calls to waddwstr() and sometimes tail of previous line is left displaying. Can ncurses just stop when right edge of window is reached?

Answer 1

The non-wrapping functions have "ch" in their name, e.g., wadd_wchstr.

The same is true of the non-wide interfaces waddstr versus waddchstr.

However, the wrapping/non-wrapping functions differ by more than that. They use different parameter types. The wrapping functions rely upon the video attributes set via wattr_set, etc., while the non-wrapping functions combine the video-attributes with the character data:

• waddstr and waddchstr use char* and chtype* parameters, respectively
• waddwstr and wadd_chstr use wchar_t* and cchar_t* parameters.

Converting between the two forms can be a nuisance, because X/Open, etc., did not define functions for doing the conversion.

The manual page for bkgd describes how these video attributes are combined with the background character to obtain the actual display.

Answer 2

The accepted answer (by Mr. Dickey) is correct. However, the "ch" functions do not work with ordinary C strings (array of bytes). Another solution is to create a wrapper for waddstr which checks the current cursor position and window size and prints only as much as would fit.

For example:

int waddstr_trunc(WINDOW *win, const char *str)
{
  int cur_x, max_x, dummy [[maybe_unused]];
  getyx(win, dummy, cur_x);
  getmaxyx(win, dummy, max_x);
  int w=max_x - cur_x;
  if (w <= 0) return 0;
  char *str2 = strndup(str, w);
  if (str2 == NULL) return 1;
  int rv = waddstr(win, str2);
  free(str2);
  return rv;
}