GTK_Pointer在C中传递结构的问题

Question

我在传递结构（指针）超出初始化它们的原始功能时遇到问题。

我注意到的是：从最初初始化该结构的函数得到的进一步信息（当我将结构从一个函数传递到下一个函数作为指针）时，我基本上开始丢失数据（或对数据的引用）。 当我尝试在struct中打印整数之一时，它将为我提供正确的值，然后转换为垃圾（可能是mem location ??），然后再次打印出该值并再次随机进行垃圾处理。

该程序：在以下程序中，我尝试创建一组5个标签，在按向上或向下按钮时可以更改其中的文本。 标签贴在事件框上，该框现在将标签的文本打印到终端上。 尝试检索文本时出现分段错误。

结果是当我尝试使用结构中的数据时（例如更改结构中的标签文本等），我遇到了段错误。

struct Alpha{
GtkWidget *alphalbl[5]; //array of label widgets
gchar *alpha[38];       //array of characters
gint start;             //start position
gint pos;               //current position
};

void createWindow(GtkWidget *widget, gpointer data){

struct Alpha alpha;     //Initialization of structure

/* Create window, layout, notebook, menu, etc*/

createList(&alpha, &layer)  //layer is a struct of fixed layouts 

}

该结构具有以下功能：

void createList(gpointer structalpha, gpointer structlayers){

GtkWidget *alphaup, *alphadn;
GtkWidget *alphabox[5];

struct Layers *layer = structlayers;
struct Alpha *alphalist = (struct Alpha *)structalpha;

gchar *alphal[] = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","S","T","U","V","W","X","Y","Z","0","1","2","3","4","5","6","7","8","9","<","[]"};

layer->fixedl = gtk_fixed_new();

for (int a = 0; a < 38; a++)                    //Add chararray to struct
    alphalist->alpha[a] = g_strdup(alphal[a]);

alphalist->start = 0;           

for(int i = 0; i < 5; i++){
    alphalist->alphalbl[i] = gtk_label_new(alphalist->alpha[i]);
    alphabox[i] = gtk_event_box_new();
    gtk_widget_set_size_request(alphabox[i], 20, 20);
    gtk_widget_set_name(GTK_WIDGET(alphabox[i]), g_strdup_printf("%d",i));
    gtk_container_add(GTK_CONTAINER(alphabox[i]), alphalist->alphalbl[i]);
    gtk_widget_set_events(alphabox[i], GDK_BUTTON_PRESS_MASK);
    //g_signal_connect(alphabox[i], "button_press_event", G_CALLBACK(setLetter), (alphalist->alphalbl[i]));    //originally tried sending just the single label
    g_signal_connect(alphabox[i], "button_press_event", G_CALLBACK(setLetter), &alphalist);  //<--struct does not send correctly
}

alphaup = gtk_button_new_with_label("^");
gtk_widget_set_size_request(alphaup, 50, 20);
g_signal_connect(alphaup, "clicked", G_CALLBACK(alphaUp), alphalist); //<--struct does not send correctly

alphadn = gtk_button_new_with_label("v");
gtk_widget_set_size_request(alphadn, 50, 20);
g_signal_connect(alphadn, "clicked", G_CALLBACK(alphaDown), alphalist); //<--struct does not send correctly

for(int y = 0; y < 5; y++)
    gtk_fixed_put(GTK_FIXED(layer->fixedl), alphabox[y], 5, (50 + (y*15)));

}

该结构不再起作用（在setLetter中）。 “->”仍会找到变量，但是运行代码时会遇到分段错误，除非我注释掉gtk_get_text ...我已经打印了alphalist->从此函数开始，只是为了使其间歇性地工作而不改变其值。 我尝试在回调中的alphalist中添加“＆”，但未成功。

void setLetter(GtkWidget *alphabox, gpointer alphal){

    struct Alpha *alphalist = alphal;   
    gchar *charnum;

    int num;
    charnum = (gtk_widget_get_name(alphabox));
    num = atoi(charnum);

    g_print(gtk_label_get_text(GTK_LABEL(alphalist->alphalbl[num])));
    g_free(charnum);

}

是否没有为结构正确分配内存的问题？ 调用malloc（）是否可以解决我的问题？ 如果可以，在哪里以及如何？ 我尝试添加它没有成功。 任何帮助将不胜感激。 先感谢您。

Answer 1

好吧，我确实有一个测试程序可以从main上脱离出来。 我必须对其稍作修改以适应我之前所做的事情。 需要注意的是，在原始程序中传递结构时，除非使用gpointer，否则会出现编译器错误。 一个函数以前在这里键入错误。 在这里，它工作得很好。 我还包括该结构的构造函数。 我将查看是否可以修改原始版本并正常工作。 谢谢...

#include <gtk/gtk.h>

struct Alpha{
     GtkWidget *label[5];
     gchar *num[10];
     gint start;
};

struct Alpha *Alpha_new(void){
     struct Alpha *p = g_malloc(sizeof *p);
}

void Alpha_delete(struct Alpha *p, gpointer data){
    g_free(p);
}

void createWindow(GtkWidget **window, struct Alpha *alpha, gint x, gint y);
void setLabel(struct Alpha *alpha, GtkWidget *button);
void printNum(struct Alpha *alpha);

void main(int argc, char** argv) {

    GtkWidget *window;

    struct Alpha *alpha;
    alpha = Alpha_new();

    gtk_init(&argc, &argv);

    createWindow(&window, alpha, 600, 400);

    gtk_widget_show_all(window);
    gtk_main();

}
void createWindow(GtkWidget **window, struct Alpha *alpha, gint x, gint y){

    GtkWidget *fixed, *label, *button;
    gchar *num[] = {"0","1","2","3","4","5","6","7","8","9"};

    *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size(GTK_WINDOW(*window), x, y);

    fixed = gtk_fixed_new();

    label = gtk_label_new("Struct Test");
    gtk_fixed_put(GTK_FIXED(fixed), label, 280, 50);

    button = gtk_button_new_with_label("TEST");
    gtk_fixed_put(GTK_FIXED(fixed), button, 280, 250);

    for(int y = 0; y < 10; y++)
        alpha->num[y] = g_strdup(num[y]);

    for(int a = 0; a < 10; a++)
        g_print(alpha->num[a]);

    g_print("----");   

    printNum(alpha);

    for(int i = 0; i < 5; i++){
        alpha->label[i] = gtk_label_new(alpha->num[i]);
        gtk_fixed_put(GTK_FIXED(fixed), (alpha->label[i]), 310, (100 + (15*i)));
    }

    alpha->start = 1;
    gtk_container_add(GTK_CONTAINER(*window), fixed);

    g_signal_connect_swapped(button, "clicked", G_CALLBACK(setLabel), alpha);
    g_signal_connect_swapped(*window, "destroy", G_CALLBACK(Alpha_delete), alpha);
 }

 void printNum(struct Alpha *alpha){
    for(int i = 0; i < 10; i++)
        g_print(alpha->num[i]);
 }

 void setLabel(struct Alpha *alpha, GtkWidget *button){
     int start = alpha->start;

     for(int i = 0; i < 5; i++){
         if(i + start > 9)
             gtk_label_set_text(GTK_LABEL(alpha->label[i]), alpha->num[(i + (start-10))]);
        else
             gtk_label_set_text(GTK_LABEL(alpha->label[i]), alpha->num[(i + start)]);
    }

    (alpha->start)++;

    if(alpha->start == 10)
        alpha->start = 0;

 }

Answer 2

g_signal_connect(alphabox[i], "button_press_event", G_CALLBACK(setLetter), &alphalist); //<--struct does not send correctly

在createlist alphalist是指向结构Alpha的指针 。 您尝试将指针传递给该指针，即，指向struct Alpha指针的指针 。 这是一个一定的错误，因为此确切值分配在堆栈上，并且当您从createlist返回时不再有效。

---

如果第一个代码块不是main而是一个函数，则会出现相同的问题。