a question about gdb in emacs

[x_uch]

Hi List:

  While i debuged application in windows that use emacs, the buffer of gdb 
can't get the output,but everything is ok while gdb run in windows by direct 
running. I don't know where the problem is, in me or the emacs.
in windows , prommpt can get the output like this:


and in emacs ,gdb buffer like this:

Here is the application which i debuged, download from sqlite site, web address 
http://www.sqlite.org/2014/sqlite-amalgamation-3080403.zip .In windows ,i 
compiled it using mingw,
using "gcc -g -o sqlite3 shell.c sqlite3.c" to build sqlite3.exe

I tried another app, source code:
-----------------------
#include <stdio.h>
typedef struct {
  float a;
  float b;
} substruct;

struct {
  int i;
  substruct r;
} c;

myproc(n)
{
  int p;
  p = 2*n;
  printf("Two times %d is %d\n", n, p);
}

main() {
  int n = 4;
  int m[10] = {0,1,4,9,16,25,36,49,64,81};
  n = 5;
  myproc(n);
  c.i = 1;
  c.r.a = 0.5;
  c.r.b = 0.25;
}
----------------
saved it to test.c,build by "gcc -o test test.c -g"
in windows and emacs gdb all can get the output "Two times 5 is 10"
so i think the problem in emacs, does anyone know where is?