ncurses threaded progress example

/* simple example of using ncurses to display a queue of progress bars
 * save this file as ncprogress.c
 * compile with gcc -o ncp ncprogress.c -pthread -lncurses
 * change MAX_BARS to the size you want your queue to be
 * run ./ncp to test it out */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <pthread.h>
#include <ncurses.h>
#define MAX_BARS 5
WINDOW *positions[MAX_BARS] = { NULL };
struct progressContext
{
        void (*callback)(unsigned, unsigned, struct progressContext *);
        WINDOW *win;
        char *name;
};
struct threadContext
{
        struct progressContext *progress;
        int position;
        unsigned seconds;
        pthread_t threadId;
};
void waitLoop(unsigned ms, unsigned interval, struct progressContext *context)
{
        unsigned i, j, s, count = ms/interval;
        for (i = 0, s = 0; i < ms; i += interval, ++s)
        {
                (*context->callback)(s % 4, (i * 100) / ms, context);
                usleep(interval * 1000);
        }
        (*context->callback)(0, 100, context);
        printf("\n");
}
void progressw(unsigned spin, unsigned step, struct progressContext *ctx)
{
        int i;
        const char *pgstep = "|\\-/";
        wclear(ctx->win);
        wprintw(ctx->win, "Your title here, this thread is %s seconds\n[", ctx->name); // print window title first
        for (i = 0; i < step; ++i) wprintw(ctx->win, "#"); // print bar
        for (; i < 100; ++i) wprintw(ctx->win, " "); // print blank space
        wprintw(ctx->win, "] %c                       ", step > 99 ? ' ' : pgstep[spin]);
        wrefresh(ctx->win);
}
void *threadWrapper(void *arg)
{
}
int selectPosition()
{
        int i;
        for (i = 0; i < MAX_BARS; ++i)
                if (positions[i] == NULL)
                        return i;
        return -1;
}
void *threadEntry(void *arg)
{
        struct threadContext *ctx;
        struct progressContext *pctx;
        ctx = arg;
        pctx = ctx->progress;
        waitLoop(ctx->seconds * 1000, 1000, pctx);
        werase(pctx->win);
        wrefresh(pctx->win);
        delwin(pctx->win);
        free(pctx->name);
        free(pctx);
        usleep(200 * 1000);
        positions[ctx->position] = NULL; // put the window back in the list
        free(ctx);
        return NULL;
}
void runThread(unsigned seconds, void (*callback)(unsigned, unsigned, struct progressContext *))
{
        int position;
        struct threadContext *ctx;
        do { position = selectPosition(); } while (position < 0); // wait until we get a window
        positions[position] = (void *)1; // reserve our spot before we create the window, we will change this later
        positions[position] = newwin(2, 120, position * 2, 0); // create an ncurses window for it
        wclear(positions[position]); wrefresh(positions[position]); // initialize the window
        ctx = malloc(sizeof(struct threadContext));
        ctx->threadId = 0;
        ctx->position = position;
        ctx->seconds = seconds;
        ctx->progress = malloc(sizeof(struct progressContext));
        ctx->progress->callback = callback;
        ctx->progress->win = positions[position];
        ctx->progress->name = malloc(8);
        sprintf(ctx->progress->name, "%d", seconds);
        ctx->threadId = pthread_create(&ctx->threadId, NULL, threadEntry, ctx);
}
int running()
{
        int i;
        for (i = 0; i < MAX_BARS; ++i)
                if (positions[i] != NULL)
                        return 1;
        return 0;
}
int main()
{
        int i;
        const int ndownloads = 18;
        initscr();
        refresh();
        noecho();
        srand(time(NULL));
        for (i = 0; i < ndownloads; ++i)
        {
                runThread(rand() % 10 + 5, &progressw); // run for random time between 5 and 10 seconds
                usleep(750 * 1000); //a time out
        }
        sleep(1); // wait for a thread to start
        while (running()); // loop while we wait
        refresh();
        endwin();
        return 0;
}