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Well, I am working on a roguelike game in which I stumbled upon some odd behaviour from ncurses' side.
Given the following code:
#include <ncurses.h>
#include <string>
#include <sstream>
bool running;
void handle_keyboard();
int main() {
std::stringstream ss;
std::string msg;
initscr();
raw();
noecho();
curs_set(0);
int loop_no=0;
running=true;
while(running) {
handle_keyboard();
clear;
ss << "Loop no. " << loop_no;
msg = ss.str();
mvprintw(1,1, msg.c_str());
ss.str("");
loop_no++;
}
endwin();
return 0;
}
void handle_keyboard() {
static char ch;
ch = getch();
switch(ch) {
case 'q':
running = false;
break;
default:
break;
}
}
the problem happens when I press arrow keys(Edit: also includes F1-F12 keys, pg up, pg down, end, home etc. keys). What happens, is that it seems as if the getch() function does not stop the execution for the 4 cycles to come. As in, the next 2 getch() functions do nothing. They are skipped. Which results in "skipped" cycles in the main loop.
The output is something like this:
if using other than arrow keys:
Loop no. 1
Loop no. 2
Loop no. 3
... etc
if using arrow keys:
loop no. 2
loop no. 5
loop no. 8
loop no. 11
loop no. 14
...
I have no clue(Might be related to enabling keypad with keypad() function though, no luck with trial-and-error so far.) why this happens. I have no proper workarounds how to prevent this. (Calling getch() twice after the 'bug' happens does fix it partly, however it adds two key stroke 'delay' to any key presses, so it's not a viable workaround.)
Tested on Linux(ArchLinux with 2.6.31 kernel) with gcc(4.4.2) and ncruses 5.7.20081102.
Any thoughts?
--
Solved it. Solution was to enable keypad after calling initscr(). I tried to do it with "keypad(0, true);", but I had to use "keypad(stdscr, true);" instead. Now it works great.
