编译iPhone设备而不是模拟器的代码

Question

我正在使用C++开发iPhone应用程序的算法部分,我遇到了一个奇怪的错误.我所拥有的代码,在Linux,Mac和iPhone设备上都可以很好地编译gcc-4.2,而不是在模拟器上,这使得调试和测试变得非常困难.

试图为模拟器编译的错误消息类似于4.0.x中的已知错误,尽管由于我已明确将gcc-4.2设置为默认编译器,因此不太清楚.

为了演示该错误,我准备了以下小代码片段:

bug.cpp

#include <tr1/unordered_map>
#include <iostream>

/* a hash key for the visitedTrip table */
struct X {
    int x;

    X() : x(0){};
    X(int x) : x(x){};
};


typedef std::tr1::unordered_map<int,X> dict;

int main() 
{ 
    dict c1; 

    X a(0);
    X b(1);
    X c(2);

    c1[0] = a;
    c1[1] = b;
    c1[2] = c;

    dict::const_iterator it;

    for(it = c1.begin(); it != c1.end(); it++)
        std::cout << it->first << std::endl;

    return (0); 
} 

然后尝试编译如下:

compile.sh

#!/bin/bash

#
# Compiling for the simulator and compiling under gcc-4.0 return the same error message
#

#SUCCESS
c++-4.2 -arch i386 bug.cpp

#FAIL 
c++-4.0 -arch i386 bug.cpp

#SUCCESS
gcc-4.2 -arch i386 -c bug.cpp

#FAIL
gcc-4.0 -arch i386 -c bug.cpp

#FAIL
gcc-4.2 -arch i386 -c bug.cpp -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk 

尽管我正在使用gcc-4.2来编译模拟器,但我得到了同样的错误信息,就像我在gcc-4.0下编译一样,即:

bug.cpp:27: error: no matching function for call to ‘Internal::hashtable_iterator<std::pair<const int, X>, false, false>::hashtable_iterator()’
/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/usr/include/c++/4.2.1/tr1/hashtable:236: note: candidates are: Internal::hashtable_iterator<Value, is_const, cache>::hashtable_iterator(const Internal::hashtable_iterator<Value, true, cache>&) [with Value = std::pair<const int, X>, bool is_const = false, bool cache = false]
/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/usr/include/c++/4.2.1/tr1/hashtable:234: note:                 Internal::hashtable_iterator<Value, is_const, cache>::hashtable_iterator(Internal::hash_node<Value, cache>**) [with Value = std::pair<const int, X>, bool is_const = false, bool cache = false]
/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/usr/include/c++/4.2.1/tr1/hashtable:232: note:                 Internal::hashtable_iterator<Value, is_const, cache>::hashtable_iterator(Internal::hash_node<Value, cache>*, Internal::hash_node<Value, cache>**) [with Value = std::pair<const int, X>, bool is_const = false, bool cache = false]
/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/usr/include/c++/4.2.1/tr1/hashtable:225: note:                 Internal::hashtable_iterator<std::pair<const int, X>, false, false>::hashtable_iterator(const Internal::hashtable_iterator<std::pair<const int, X>, false, false>&)

关于为什么这个gcc-4.0.x bug会进入模拟器的任何想法,实际上模拟器应该使用gcc-4.2.x,其中这个bug已被修复？

Answer 1

不确定这是否是正确的答案，但这可能可以解释为什么您在使用 4.2 时会看到 4.0 的行为：

> pwd
/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.1.sdk/usr/include/c++
> ls -l
total 4
drwxr-xr-x  10 root  wheel  2278 10 Sep 09:32 4.0.0/
lrwxr-xr-x   1 root  wheel     5 10 Sep 09:30 4.2.1@ -> 4.0.0

看起来他们正在尝试为两个版本使用 4.0 标头集，至少在带有 Xcode 3.2 的 Snow Leopard 上是这样。