GTK+ front-end wrapper around the UNIX which(1) command

gwhich.c

/* gwhich.c -by Ryan Kulla 
 * GTK+ front-end wrapper around the which(1) command.
 * Compile with: gcc gwhich.c -o gwhich `pkg-config --cflags --libs gtk+-2.0`
 * Usage: gwhich
 */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <gtk/gtk.h>

GtkWidget *get_window(void);
void build_window(GtkWidget *window, char *title);
GtkWidget *get_vbox(GtkWidget *window);
void show_vbox(GtkWidget *window, GtkWidget *vbox);
GtkWidget *get_entry(void);
void build_entry(GtkWidget *vbox, GtkWidget *entry);
void enter_callback(GtkWidget *widget, GtkWidget *entry);
GtkWidget *get_frame(void);
void build_label_frame(GtkWidget *vbox, GtkWidget *frame);
GtkWidget *get_hbox(void);
void show_hbox(GtkWidget *vbox, GtkWidget *hbox);
GtkWidget *get_button(char *msg);
GtkWidget *build_button(GtkWidget *window, GtkWidget *vbox, GtkWidget *button);

GtkWidget *label;
gchar *result_path;

GtkWidget *get_window(void) {
    return gtk_window_new(GTK_WINDOW_TOPLEVEL);
}

void build_window(GtkWidget *window, char *title) {
    gtk_widget_set_usize(GTK_WIDGET(window), 255, 200);
    gtk_window_set_title(GTK_WINDOW(window), title);
    gtk_signal_connect(GTK_OBJECT(window), "delete_event",
        (GtkSignalFunc) gtk_exit, NULL);
}

GtkWidget *get_vbox(GtkWidget *window) {
    return gtk_vbox_new(FALSE, 0);
}

void show_vbox(GtkWidget *window, GtkWidget *vbox) {
    gtk_container_add(GTK_CONTAINER(window), vbox);
    gtk_widget_show(vbox);
}

GtkWidget *get_entry(void) {
    return gtk_entry_new_with_max_length(256);

}

void build_entry(GtkWidget *vbox, GtkWidget *entry) {
    gtk_signal_connect(GTK_OBJECT(entry), "activate", GTK_SIGNAL_FUNC(enter_callback), entry);
    gtk_entry_set_text(GTK_ENTRY(entry), "some");
    gtk_entry_append_text(GTK_ENTRY(entry), " command");
    gtk_entry_select_region(GTK_ENTRY(entry), 0, GTK_ENTRY(entry)->text_length);
    gtk_box_pack_start(GTK_BOX(vbox), entry, TRUE, TRUE, 0);
}

void enter_callback(GtkWidget *widget, GtkWidget *entry) {
    char buf[256], *cp, command[256], no_match[100];
    FILE *p;

    result_path = gtk_entry_get_text(GTK_ENTRY(entry));

    sprintf(command, "which %s", result_path);
    sprintf(no_match, "Can't find %s", result_path);

    p = popen(cp = command, "r");

    while (fgets(buf, sizeof buf, p) != 0);

    if (buf[0] != '/') {
        gtk_label_set_text(GTK_LABEL(label), no_match);
    } else {
        gtk_label_set_text(GTK_LABEL(label), buf);
    }

    pclose(p);
}

GtkWidget *get_frame(void) {
    return gtk_frame_new("Path: ");
}

void build_label_frame(GtkWidget *vbox, GtkWidget *frame) {
    label = gtk_label_new(result_path);
    gtk_container_add(GTK_CONTAINER(frame), label);
    gtk_box_pack_start(GTK_BOX(vbox), frame, FALSE, FALSE, 0);
}

GtkWidget *get_hbox(void) {
    return gtk_hbox_new(FALSE, 0);
}

void show_hbox(GtkWidget *vbox, GtkWidget *hbox) {
    gtk_container_add(GTK_CONTAINER(vbox), hbox);
    gtk_widget_show(hbox);
}

GtkWidget *get_button(char *msg) {
    return gtk_button_new_with_label(msg);
}

GtkWidget *build_button(GtkWidget *window, GtkWidget *vbox, GtkWidget *button) {
    gtk_signal_connect_object(GTK_OBJECT(button), "clicked",
        GTK_SIGNAL_FUNC(gtk_exit), GTK_OBJECT(window));
    gtk_box_pack_start(GTK_BOX(vbox), button, TRUE, TRUE, 0);
    GTK_WIDGET_SET_FLAGS(button, GTK_CAN_DEFAULT);
    gtk_widget_grab_default(button);
}

int main(int argc, char *argv[]) {
    GtkWidget *window, *vbox, *hbox, *entry, *button, *frame;

    gtk_init(&argc, &argv);

    window = get_window();
    build_window(window, "which(1) GUI");

    vbox = get_vbox(window);
    show_vbox(window, vbox);

    entry = get_entry();
    build_entry(vbox, entry);
    gtk_widget_show(entry);

    frame = get_frame();
    build_label_frame(vbox, frame);
    gtk_widget_show(label);
    gtk_widget_show(frame);

    hbox = get_hbox();
    show_hbox(vbox, hbox);

    button = get_button("Close");
    build_button(window, vbox, button);
    gtk_widget_show(button);

    gtk_widget_show(window);
    gtk_main();

    return(0);
}