Example: Integrating readline with libev eventloop.

readline_ev.cpp

// g++ -o readline_ev -g readline_ev.cpp -g -lreadline -lev
//
#include <stdlib.h>
#include <unistd.h>
#include <readline/readline.h>
#include <readline/history.h>
#include <ev.h>
#include <fcntl.h>


// The function that'll get passed each line of input
void my_rlhandler(char* line) {

    if (line==NULL) {
        // Ctrl-D will allow us to exit nicely
        printf("\nNULLBURGER\n");
    } else {
        if (*line!=0) {
            // If line wasn't empty, store it so that uparrow retrieves it
            add_history(line);
        }
        printf("Your input was:\n%s\n", line);
        free(line);
    }
}


// all watcher callbacks have a similar signature
// this callback is called when data is readable on stdin
static void stdin_cb(EV_P_ ev_io *w, int revents)
{
    if (revents & EV_READ) {
        rl_callback_read_char();
    }
}

ev_timer timeout_watcher;

static void timeout_cb(EV_P_ struct ev_timer* w, int revents)
{
    puts(".");
}

int main(int argc, char **argv)
{
    fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);

    const char *prompt = "WOOP> ";
    // Install the handler
    rl_callback_handler_install(prompt, (rl_vcpfunc_t*) &my_rlhandler);

    // setup libev
    struct ev_loop *loop = EV_DEFAULT;
    ev_io stdin_watcher;
    ev_io_init(&stdin_watcher, stdin_cb, fileno(stdin), EV_READ);

    // initialize an timer watcher
    // the timeout event will occur after 1sec, and repeat every 2sec
    ev_timer_init(&timeout_watcher, timeout_cb, 1, 2);
    ev_timer_start(loop, &timeout_watcher);

    ev_io_start(loop, &stdin_watcher);

    // start libev
    ev_loop(loop, 0);

    rl_callback_handler_remove();
    return 0;
}