判断C运行时环境的程序

/*_############################################################################
  _##
  _##  判断C运行时环境的程序
  _##  Author: xwlee                        
  _##  Time: 2007.01.02 
  _##  Chang'an University
  _##  Development condition: win2003 Server+VC6.0
  _##
  _##  runtime.cpp 文件
  _##########################################################################*/

// 静态初始化.
int static_variable = 5;

void f()
{
    register int i1, i2, i3, i4, i5, i6, i7, i8, i9, i10;
    register char *c1, *c2, *c3, *c4, *c5, *c6, *c7, *c8, *c9,*c10;
    extern int a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be;
    double dbl;
    int func_ret_int( int a, int b, register int c);
    double func_ret_double();
    char *func_ret_char_ptr( char *cp );

    // 寄存器变量的最大数量.
    i1 = 1;  i2 = 2;  i3 = 3;  i4 = 4;  i5 = 5;
    i6 = 6;  i7 = 7;  i8 = 8;  i9 = 9;  i10 = 10;
    c1 = (char *)110;  c2 = (char *)120;
    c3 = (char *)130;  c4 = (char *)140;
    c5 = (char *)150;  c6 = (char *)160;
    c7 = (char *)170;  c8 = (char *)180;
    c9 = (char *)190;  c10 = (char *)200;

    // 外部名字.
    a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be_a_very_long_name_to_sec_how_long_they_can_be = 1;

    // 函数调用/返回协议，堆栈帧（过程活动记录）.
    i2 = func_ret_int( 10, i1, i10 );
    dbl = func_ret_double();
    c1 = func_ret_char_ptr( c1 );
}

int func_ret_int( int a, int b, register int c )
{
    int d;

    d = b - 6;
    return a + b + c;
}

double func_ret_double()
{
    return 3.14;
}

char *func_ret_char_ptr( char *cp )
{
    return cp + 1;
}