c - 当我编译我的内核时，是什么导致了这个奇怪的警告？传递不兼容的指针类型，期望结构 * 但得到结构 *

Question

我希望有人能给我解释一下。我正在编写自己的操作系统，并着手编写内存管理器。编译内核时，我不断收到奇怪的警告。这个警告对我来说很矛盾。该函数正在获取它期望的参数类型，但好像不是这样提示。一切运行良好，我能够获得初始化内存管理器所需的信息。你能告诉我这是什么原因造成的吗？

$HOME/opt/cross/bin/i686-elf-gcc -c -ffreestanding -O2 -Wall -Wextra -std=gnu99 -ggdb -isystem src/h -o build/kernel.c.o src/c/kernel.c

src/c/kernel.c: In function 'kernel_main': src/c/kernel.c:29:2: warning: passing argument 1 of 'memory_manager_initialize' from incompatible pointer type

memory_manager_initialize(mboot_ptr); // wtf does this cause a warning?

In file included from src/h/system.h:39:0, from src/h/multiboot.h:4, from src/c/kernel.c:1:

src/h/memory.h:35:6: note: expected 'struct multiboot *' but argument is of type 'struct multiboot *'

void memory_manager_initialize(struct multiboot *mboot_ptr);

这是 GRUB 调用的加载程序的代码。

# Declare constants used for the multiboot header
.set ALIGN,        1<<0
.set MEMINFO,    1<<1
.set MAGIC,        0x1BADB002
.set FLAGS,        ALIGN | MEMINFO
.set CHECKSUM,    -(MAGIC + FLAGS)

.global .multiboot
.extern code
.extern bss
.extern end

.section .multiboot
    #.align 4
    .long MAGIC
    .long FLAGS
    .long CHECKSUM
    .long .multiboot
    .long code
    .long bss
    .long end
    .long _start

.section .text
    .global _start
    .extern kernel_main
    .type _start, @function
    _start:
        push %esp
        push %ebx
        cli
        call kernel_main
        .hang:
            jmp .hang

.size _start, . - _start

这是警告来 self 的内核的代码。

int kernel_main(struct multiboot *mboot_ptr, u32int initial_stack)
{
    initial_esp = initial_stack;

    gdt_initialize();
    idt_initialize();
    memset((u8int *) &interrupt_handler, 0, sizeof(isr) * 256);

    enable_interrupts();
    timer_initialize(100);
    keyboard_initialize();
    keyboard_set_handler(kernel_keyboard_handler);
    vga_set_handler(kernel_vga_handler);
    memset((u8int *) terminal_buffer, 0, MAX_TERMINAL_BUFFER_SIZE); // clear the terminal buffer (initalize it to 0 when we start running)

    // i need to get the memory management going.
    memory_manager_initialize(mboot_ptr);    // wtf does this cause a warning?

被调用的函数定义为

void memory_manager_initialize(struct multiboot *mboot_ptr)

Answer 1

要么你的结构被定义为:

typedef struct {
    /*  Stuff  */
} multiboot;

什么时候应该定义为:

typedef struct multiboot {    //  Note difference in this line
    /*  Stuff  */
} multiboot;

或者您的 memory_manager_initialize() 函数原型(prototype)出现在编译器看到您的 struct multiboot 定义之前。