编译我自己的内核（而不是从Linux内核源）

Question

我从以下编译我的文件here

的具有1M的问题内核教程。

我碰到下面的错误，当我试图编译：

main.c:8: error: expected declaration specifiers or ‘...’ before ‘size_t’ 
main.c:8: error: conflicting types for ‘memcpy’       
./include/system.h:5: note: previous declaration of ‘memcpy’ was here  
main.c: In function ‘memcpy’:            
main.c:12: error: ‘count’ undeclared (first use in this function)   
main.c:12: error: (Each undeclared identifier is reported only once  
main.c:12: error: for each function it appears in.)      
main.c: At top level:              
main.c:16: error: expected declaration specifiers or ‘...’ before ‘size_t’ 
main.c:16: error: conflicting types for ‘memset’ 
./include/system.h:6: note: previous declaration of ‘memset’ was here 
main.c: In function ‘memset’: 
main.c:19: error: ‘count’ undeclared (first use in this function) 
main.c: At top level: 
main.c:23: error: expected declaration specifiers or ‘...’ before ‘size_t’ 
main.c:23: error: conflicting types for ‘memsetw’ 
./include/system.h:7: note: previous declaration of ‘memsetw’ was here 
main.c: In function ‘memsetw’: 
main.c:26: error: ‘count’ undeclared (first use in this function) 
main.c: At top level: 
main.c:30: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘strlen’ 
main.c:49: warning: return type of ‘main’ is not ‘int’ 
main.c: In function ‘main’: 
main.c:64: warning: pointer targets in passing argument 1 of ‘puts’ differ in signedness 
./include/system.h:13: note: expected ‘unsigned char *’ but argument is of type ‘char *’ 
main.c:51: warning: unused variable ‘i’ 
scrn.c: In function ‘scroll’: 
scrn.c:24: warning: passing argument 1 of ‘memcpy’ from incompatible pointer type 
./include/system.h:5: note: expected ‘unsigned char *’ but argument is of type ‘short unsigned int *’ 
scrn.c:24: warning: passing argument 2 of ‘memcpy’ from incompatible pointer type 
./include/system.h:5: note: expected ‘const unsigned char *’ but argument is of type ‘short unsigned int *’ 
scrn.c: In function ‘puts’: 
scrn.c:139: warning: pointer targets in passing argument 1 of ‘strlen’ differ in signedness 
./include/system.h:8: note: expected ‘const char *’ but argument is of type ‘unsigned char *’ 

我的文件是从教程中的的精确副本。
我可以看到，在main.c中的函数定义，像这样

void *memcpy(void *dest,const void *src, size_t count)

但在我system.h中文件它们像这样

extern unsigned char *memcpy(unsigned char *dest,const unsigned char *src, int count)

C中定义不是我主要的语言，但我正在学习它的过程中，所以我道歉，如果我的问题很简单，但我会认为这些定义应该是相同的？

Answer 1

可能是您的问题size_t与您的平台上的int不一样，或者size_t没有正确指定。指针类型应该是OK的（技术上，它们也应该匹配，但是在大多数系统上sizeof(char*) == sizeof(void*)）。

如果您正在开发自己的内核，那么您需要编写自己的system.h。如果您同时编写system.h和main.c，则可以根据需要将它们匹配起来。如果你看一下this page of the tutorial，你会看到标题和C源都声明memcpy为：

unsigned char *memcpy(unsigned char *dest, const unsigned char *src, int count); 

但是，如果你下载示例源文件在教程的最后，你会发现它是不是：

void *memcpy(void *dest, const void *src, size_t count); 

望着那文件的顶部，你会发现这样的评论：

/* bkerndev - Bran's Kernel Development Tutorial 
* By: Brandon F. (friesenb@gmail.com) 
* Desc: Main.c: C code entry. 
* 
* Notes: No warranty expressed or implied. Use at own risk. */ 

它看起来并不像你想跟随的教程，但RA那么你试图从教程中剪切和粘贴代码。这就像试图通过一本书一起学习进行脑部手术一样。你可能会得到它的工作，但如果你真的不明白你在做什么...好吧，请为世界帮忙，不要用它来做任何关键的事情。

Answer 2

在每个方法定义为int替换上的main.c