c - 在结构初始化中定义常量

我尝试遵循以下link来初始化我的数据：

struct dmparam {
    char *p;
    char *v;
};

struct dmobj {
    int a;
    int b;
    const struct dmparam * const *dmparam;
};


const struct dmobj dmobj[] = {
    {1, 11, NULL},
    {2, 22,
        (struct dmparam  * const []) {//params
        {"p1", "v1"},
        {"p2", "v2"},
        }//params
    },
    {3, 33, NULL},
};

但是我在汇编中收到警告

test.c:35:3: warning: braces around scalar initializer [enabled by default]
   {"p1", "v1"},
   ^
test.c:35:3: warning: (near initialization for ‘(anonymous)[0]’) [enabled by default]
test.c:35:3: warning: initialization from incompatible pointer type [enabled by default]
test.c:35:3: warning: (near initialization for ‘(anonymous)[0]’) [enabled by default]
test.c:35:3: warning: excess elements in scalar initializer [enabled by default]
test.c:35:3: warning: (near initialization for ‘(anonymous)[0]’) [enabled by default]
test.c:36:3: warning: braces around scalar initializer [enabled by default]
   {"p2", "v2"},
   ^
test.c:36:3: warning: (near initialization for ‘(anonymous)[1]’) [enabled by default]
test.c:36:3: warning: initialization from incompatible pointer type [enabled by default]
test.c:36:3: warning: (near initialization for ‘(anonymous)[1]’) [enabled by default]
test.c:36:3: warning: excess elements in scalar initializer [enabled by default]
test.c:36:3: warning: (near initialization for ‘(anonymous)[1]’) [enabled by default]
test.c:38:2: warning: initialization from incompatible pointer type [enabled by default]
  },
  ^
test.c:38:2: warning: (near initialization for ‘dmobj[1].dmparam’) [enabled by default]

我想念的是什么？

最佳答案

您只是缺少两个索引级别。 dmobj::dmparam是（在指向 struct dmparam **的（const）指针的dmparam的时刻忘记const。

编译器尝试使用dmparam数组直接初始化，而不是使用指向指针的指针进行初始化。叮当警告是明确的：不兼容的指针类型使用类型为'char [3]'的表达式初始化'struct dmparam * const'。编译器不够聪明，无法猜测您想要什么...

您必须在此处明确：

const struct dmparam  params [] = {
        {"p1", "v1"},
        {"p2", "v2"},
};

const struct dmparam * const p = params;

const struct dmobj dmobj[] = {
    {1, 11, NULL},
    {2, 22, &p },
    {3, 33, NULL},
};

这里的params是const dmparam的数组，p是指向params的const指针（另一个变量），然后将p的地址放在dmobj[1]中。

关于c - 在结构初始化中定义常量，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/32038121/