curs_delch.3x man page
delch, wdelch, mvdelch, mvwdelch — delete character under the cursor in a curses window
int wdelch(WINDOW *win);
int mvdelch(int y, int x);
int mvwdelch(WINDOW *win, int y, int x);
These routines delete the character under the cursor; all characters to the right of the cursor on the same line are moved to the left one position and the last character on the line is filled with a blank. The cursor position does not change (after moving to y, x, if specified). (This does not imply use of the hardware delete character feature.)
All routines return the integer ERR upon failure and an OK (SVr4 specifies only "an integer value other than ERR") upon successful completion.
Functions with a "mv" prefix first perform a cursor movement using wmove, and return an error if the position is outside the window, or if the window pointer is null.
Note that delch, mvdelch, and mvwdelch may be macros.
These functions are described in the XSI Curses standard, Issue 4. The standard specifies that they return ERR on failure, but specifies no error conditions.