【cocos2dx】android编译之ctime:66: error: ‘::clock_t’ has not been declared

本文解决了一个关于C++编译过程中出现的ctime错误问题,该问题源于自定义文件名与标准库文件名冲突导致的编译器大小写敏感问题。
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编译android 报错,ctime:66: error: ‘::clock_t’ has not been declared,诡异的问题如下图:


报一个gnu的C++标准库的ctime的错误

程序中根本木有调用<ctime>,那这个诡异的问题是怎么来的呢?


后来发现我有一个类Time.h和Time.cpp,对就是这货,且不管为什么GNU为什么不识别大小写,为什么和标准库的<time.h>起冲突,但这个诡异的问题足以告诉我们:

一定不要起类名和标准库一样的名字,否则暂时木有问题,早晚会自食苦果的~~


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国外的盆友也遇到类似的问题:给个copy

So I lost a bit of time to this compiler error coming from a MacBook and OSX 10.5:


/usr/include/c++/4.0.0/ctime:66: error: ‘::clock_t’ has not been declared
/usr/include/c++/4.0.0/ctime:68: error: ‘::tm’ has not been declared
/usr/include/c++/4.0.0/ctime:70: error: ‘::clock’ has not been declared
/usr/include/c++/4.0.0/ctime:71: error: ‘::difftime’ has not been declared
/usr/include/c++/4.0.0/ctime:72: error: ‘::mktime’ has not been declared
/usr/include/c++/4.0.0/ctime:73: error: ‘::time’ has not been declared
/usr/include/c++/4.0.0/ctime:74: error: ‘::asctime’ has not been declared
/usr/include/c++/4.0.0/ctime:75: error: ‘::ctime’ has not been declared
/usr/include/c++/4.0.0/ctime:76: error: ‘::gmtime’ has not been declared
/usr/include/c++/4.0.0/ctime:77: error: ‘::localtime’ has not been declared
/usr/include/c++/4.0.0/ctime:78: error: ‘::strftime’ has not been declared
/usr/include/c++/4.0.0/bits/locale_facets.tcc: In member function ‘_InIter std::time_get<_CharT, _InIter>::_M_extract_via_format(_InIter, _InIter, std::ios_base&, std::_Ios_Iostate&, tm*, const _CharT*) const’:
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1794: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1801: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1809: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1816: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1828: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1835: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1838: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1850: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1855: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1863: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1867: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1887: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1923: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc:1931: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc: In member function ‘virtual _InIter std::time_get<_CharT, _InIter>::do_get_weekday(_InIter, _InIter, std::ios_base&, std::_Ios_Iostate&, tm*) const’:
/usr/include/c++/4.0.0/bits/locale_facets.tcc:2157: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc: In member function ‘virtual _InIter std::time_get<_CharT, _InIter>::do_get_monthname(_InIter, _InIter, std::ios_base&, std::_Ios_Iostate&, tm*) const’:
/usr/include/c++/4.0.0/bits/locale_facets.tcc:2203: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’
/usr/include/c++/4.0.0/bits/locale_facets.tcc: In member function ‘virtual _InIter std::time_get<_CharT, _InIter>::do_get_year(_InIter, _InIter, std::ios_base&, std::_Ios_Iostate&, tm*) const’:
/usr/include/c++/4.0.0/bits/locale_facets.tcc:2230: error: invalid use of undefined type ‘struct tm’
/usr/include/wchar.h:152: error: forward declaration of ‘struct tm’


The answer is that is that the Mac OS X GCC compile environment is funny about case sensitivity and redefining things. In this case somewhere in my -I/mylibpath/include/ was a file Time.h. The system saw this as a redefinition of time.h and got all confused. Note that I didn’t even use that Time.h in my main.c, nor did any header I used call it. It just saw the file from my -I/path/. I renamed the file to oTime.h and did a find/replace on all affected library files and I was on to the next compiler error. Of course that turned out to be an undefined INT_MAX. Same problem different file. In the includes, there was a Limits.h that included limits.h but added to defines. Once again, Limits.h becomes oLimits.h and a find/replace (I’m playing with TextWrangler for this). Good luck.


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<think>好的,我现在要解决用户遇到的C++编译错误,具体是‘::clock’未声明的问题。用户提到他们使用的是GCC 8版本,并且错误信息是关于ctime中的clock未声明。我需要根据用户提供的引用和系统指令来生成解决方案和相关问题。 首先,我需要理解这个错误的原因。根据引用[1]中的情况,当使用C99标准时,可能会出现类似的问题,因为某些宏定义没有正确设置。用户的问题可能与头文件的包含顺序或编译器选项有关。另外,引用[3]提到GCC编译C++程序的流程,可能涉及到预处理阶段的问题。 接下来,我应该检查用户是否在代码中正确包含了<ctime>头文件,因为clock函数通常在ctime中声明。如果用户已经包含了该头文件,那么问题可能出在编译器选项或宏定义上。例如,在引用[1]中,用户通过定义_POSIX_C_SOURCE宏解决了问题,这可能是因为某些特性需要特定的POSIX版本支持。 考虑到用户使用的是GCC 8,可能还需要检查是否启用了C++标准版本,比如-std=c++11或更高版本,这些标准可能要求不同的宏定义。此外,检查代码中是否有其他可能影响头文件包含的宏或编译器选项也很重要。 然后,我需要综合这些信息,给出具体的解决步骤。比如,首先确保包含ctime头文件,然后检查是否需要定义特定的宏,或者在编译命令中添加必要的选项。此外,参考引用[1]中的解决方案,添加-D_POSIX_C_SOURCE=199309L到编译选项可能会解决问题。 最后,生成相关问题,需要考虑用户可能进一步遇到的编译问题,比如其他未声明的标识符、GCC版本兼容性问题,或者不同C++标准的影响。这些问题可以帮助用户扩展他们的知识,解决类似的问题。</think>### 问题分析 `‘::clock’未声明`错误通常与C/C++标准库的兼容性相关。在C++中,`clock()`函数定义在头文件`<ctime>`中,且需要符合特定编译标准。结合引用[1][^1]和引用[3][^3]的编译环境配置,以下是解决方案: --- ### 解决方案 #### 1. **检查头文件包含** 确保代码中正确包含`<ctime>`头文件: ```cpp #include <ctime> // 使用C++标准库的clock() ``` --- #### 2. **添加宏定义** 若已包含头文件仍报错,可能是POSIX标准未启用。在代码文件**最顶部**添加宏定义: ```cpp #define _POSIX_C_SOURCE 199309L // 启用clock()相关定义 #include <ctime> ``` --- #### 3. **修改编译选项** 在编译命令中直接添加宏定义(适用于命令行): ```bash g++ -D_POSIX_C_SOURCE=199309L your_code.cpp -o output ``` 或通过CMake添加(引用[1]的类似方法): ```cmake add_compile_options(-D_POSIX_C_SOURCE=199309L) ``` --- #### 4. **检查GCC编译标准** 确认编译时未强制使用过于严格的C++标准,例如: ```bash g++ -std=c++11 your_code.cpp # 优先选择C++11及以上标准 ``` --- ### 原因解释 - `clock()`函数依赖于POSIX标准,而GCC默认可能未启用相关宏。 - 在严格模式下(如`-std=c++11`),GCC会禁用部分POSIX扩展功能,需手动启用。 ---
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