extern char *a声明的是一个指针变量而不是字符数组，因此与实际的定义不同，从而造成运行时非法访问。应该将声明改为extern char a[ ]。 2)、例子分析如下，如果a[] = "abcd",则外部变量a=0x61626364 (abcd的ASCII码值)，*a显然没有意义

Hi all, I want to use P/Invoke method to call a C++ DLL, the C++ DLL has a callback function which defined as: typedef long (CALLBACK * readFileData)(unsigned char * data, int length);

If you want your octets signed, use sbyte (domain -128 through +127). 2010-06-08 在单片机C语言中，extern unsigned long ... 27 2018-12-22 c语言编程里的extern unsigned char Rx... 1 2009-12-07 c语言中的extern是什么，有什么作用啊？
byte[] state_buf = new byte[5125] ; byte is an unsigned 8-bit number with the domain 0-255. unsigned char state_buf[5125] ; try the C#. public extern int fuc1(int arg1, out IntPtr arg2, out IntPtr arg3); The arg2 has to … I have to call a win32 dll function.

Same as the byte datatype.
unsigned char ** equivalent in c# and have to write the return value in a file. int func1(int arg1, unsigned char *arg2, int *arg3); and i wrote wrapped c# as. The Arduino Reference text is licensed under a Creative Commons Attribution-Share Alike 3.0 License. 应该这样用： 在一个cpp文件中定义： extern unsigned const char ary[7]={1,2,3,4,5,6,7}; 在另一个文件中用 unsigned char ary[7]; extern int foo (int arg1, char arg2); Since the extern keyword extends the the function’s visibility to the whole program, the function can be used (called) anywhere in any of the files of the whole program, provided those files contain a declaration of the function. The unsigned char datatype encodes numbers from 0 to 255. ... An unsigned data type that occupies 1 byte of memory. For consistency of Arduino programming style, the byte data type is to be preferred.