小编Bos*_*iaw的帖子

例如:

code1.c/.cpp

int a;

// ... and so on

code2.c/.cpp

int a;

int main(void) {
    return 0;
}

去编译:

$gcc code1.c code2.c      # this is fine
$

$g++ code1.cpp code2.cpp  # this is dead
/tmp/ccLY66HQ.o:(.bss+0x0): multiple definition of `a'
/tmp/ccnIOmPC.o:(.bss+0x0): first defined here
collect2: ld returned 1 exit status

C&C++之间是否存在全局变量链接差异？

可能重复:
如何使用整数等名称访问对象属性？

print_r($myObj) 给出以下结果:

stdClass Object
(
    [4021450] => stdClass Object
    (
        [property1] => ooo
        [property2] => xxx
    )
    [3971601] => stdClass Object
    (
        [property1] => 123
        [property2] => 356
    )
)

如何使用大括号语法和变量来访问sub-object？

我试过了:

$myObj->'3971601';                     // Parse error: syntax error  
$myObj->{'3971601'};                   // Works  
$id = 3971601; $myObj->{$id};          // Notice: Trying to get property of non-object  
$id = 3971601; $myObj->{''.$id};       // Notice: Trying to get property of non-object  
$arr = (array)$myObj; $arr[3971601];   // Notice: Undefined offset: 3971601
$arr = …