Different behavior in Linux and Mac OS X

[Sebastiano Vigna]

The following program:

#include <curses.h>
#include <term.h>

int main() {
        tputs(tgoto("\x1b[%i%p1%d;%p2%dH", 1, 1), 1, putchar);
}

when compiled under Linux (Fedora 33) with ncurses 6.2, does not output 
anything. On Mac OS X (11.2.3), using ncurses 6.2 in MacPorts, it outputs the 
required cursor-positioning string.

strace/dtruss show that in the first case there is no call to a system output 
function (in the second case, of course, there is).

In ne (the nice editor) we give the option to use tputs/tgoto without setting 
up a terminal with setupterm(), relying on hardwired ANSI sequences. I'm pretty 
sure this was working under all platforms, but apparently somewhere in the last 
few years there was a change, either in the library or in the packaging by 
Fedora, that make that stop working on Linux.

Of course, is setupterm() is called before calling tputs() the output is 
correct even under Linux.

I don't even know if this is technically a bug of ncurses, but if this rings a 
bell, or anyone can suggest how to determine why the library is behaving in a 
different way, or suggest a workaround that make the program above works under 
Linux, that'd be great...

Ciao,

                                        seba