GIOChannel problem

This is a discussion on GIOChannel problem within the Linux Programming forums, part of the Platform Specific Boards category; I want to execute a program from my GTK+ application and get it's stdout output. After a little research I've ...

  1. #1
    Registered User
    Join Date
    Jun 2004
    Posts
    84

    GIOChannel problem

    I want to execute a program from my GTK+ application and get it's stdout output. After a little research I've turned to glibs GIOChannel. But I can't figure it out how can I detect the end of input. The only way I can think of is calling "wait_pid" with WNOHANG from my callback function, but somehow I think there's better way... Can anyone point me in the right direction?
    That's what I have so far:
    Code:
    #include <glib.h>
    
    #include <stdlib.h>
    #include <unistd.h>
    #include <sys/types.h>
    
    GIOChannel *io_channel_open(char *cmd[]);
    gboolean cb_read_line(GIOChannel *io_channel, GIOCondition condition, gpointer data);
    
    int main(int argc, char *argv[])
    {
        GMainLoop *main_loop;
        GIOChannel *io_channel;
        char *cmd[] = {"ls", "-lah", NULL};
    
        io_channel = io_channel_open(cmd);
        g_io_add_watch(io_channel, G_IO_IN, cb_read_line, NULL); /* Adds 1 reference...*/
        g_io_channel_unref(io_channel); /* ... so we don't need this one, I think */
    
        /* Main Loop */
        main_loop = g_main_loop_new(NULL, TRUE);
        g_main_loop_run(main_loop);
    
        return 0;
    }
    
    /* Executes the program described by cmd[]
     * and creates GIOChannel
     */
    GIOChannel *io_channel_open(char *cmd[])
    {
        GIOChannel *io_channel;
        pid_t child_pid;
        int   fd_pipe[2];
    
        pipe(fd_pipe);
        child_pid = fork();
    
        if (child_pid == 0) {
            close(fd_pipe[0]);
            dup2(fd_pipe[1], STDOUT_FILENO);
    
            execvp(cmd[0], cmd);
            g_error("exec() failed!\n");
            abort();
        }
        else {
            close(fd_pipe[1]);
            io_channel = g_io_channel_unix_new(fd_pipe[0]);
    
            return io_channel;
        }
    }
    
    /* Callback function to read and
     * process the input
     */
    gboolean cb_read_line(GIOChannel *io_channel, GIOCondition condition, gpointer data)
    {
        gchar *line_buf;
        gsize length, terminator_pos;
    
        g_io_channel_read_line(io_channel, &line_buf, &length, &terminator_pos, NULL);
        g_print("%s", line_buf);
    
        /* In _theory_ I should return FALSE to destroy this io_channel. */
        return TRUE;
    }
    I'm using to compile:
    Code:
    gcc -Wall -o pipe_koe main.c `pkg-config --cflags --libs glib-2.0`

  2. #2
    Registered User
    Join Date
    Jun 2004
    Posts
    84
    hmm... it seems I haven't been reading glib reference manual close enouhg. I just needed to add watch for hangup condition (G_IO_HUP).

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Need help understanding a problem
    By dnguyen1022 in forum C++ Programming
    Replies: 2
    Last Post: 04-29-2009, 05:21 PM
  2. Memory problem with Borland C 3.1
    By AZ1699 in forum C Programming
    Replies: 16
    Last Post: 11-16-2007, 11:22 AM
  3. Someone having same problem with Code Block?
    By ofayto in forum C++ Programming
    Replies: 1
    Last Post: 07-12-2007, 09:38 AM
  4. A question related to strcmp
    By meili100 in forum C++ Programming
    Replies: 6
    Last Post: 07-07-2007, 03:51 PM
  5. WS_POPUP, continuation of old problem
    By blurrymadness in forum Windows Programming
    Replies: 1
    Last Post: 04-20-2007, 07:54 PM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21