为什么用vc不能使用setbuffer函数?

C/C++ code

#include <stdio.h>#include <string.h>int main(int argc, char** argv){   static char stdin_buffer[65536];   static char stdout_buffer[65536];   static unsigned char predict_map[256][256];   unsigned char prev_char1 = 0;   unsigned char prev_char2 = 0;   unsigned char block[8];   unsigned char flag_byte = 0;   int flag_pos = 0;   int block_pos = 0;   int i;   int next_char;   int out_char;   setbuffer(stdin, stdin_buffer, sizeof(stdin_buffer));   setbuffer(stdout, stdout_buffer, sizeof(stdout_buffer));

warning C4013: 'setbuffer' undefined; assuming extern returning int

为何???用vs2010也是这样?

[解决办法]
什么时候有一个setbuffer()函数？
我只记得有setbuf()和setvbuf()……