C++编译错误NetBSD':: system'尚未声明

Question

我有一些C++代码可以很好地在Linux上编译，但到目前为止我无法在NetBSD上正确编译它。

这些都是我的，包括：

#include <fstream> 
#include <iostream> 
#include <cstdlib> 
#include <unistd.h> 
#include <iomanip> 
#include <boost/regex.hpp> 

我用这个命令编译：

g++ -v -O2 -fno-strict-aliasing -I /usr/pkg/include \ 
barefoot.cpp -o barefoot -L /usr/pkg/lib/ -lboost_regex \ 
-L /usr/pkg/lib/ -lboost_regex -lpthreads 

这使得这样的输出：

Using built-in specs. 
COLLECT_GCC=g++ 
Target: x86_64--netbsd 

Configured with: /usr/src2/tools/gcc/../../external/gpl3/gcc/dist/configure --target=x86_64--netbsd --enable-long-long --enable-threads --with-bugurl=http://www.NetBSD.org/Misc/send-pr.html --with-pkgversion='NetBSD nb2 20111202' --enable-__cxa_atexit --with-tune=nocona --with-mpc=/var/obj/mknative/amd64/usr/src2/destdir.amd64/usr --with-mpfr=/var/obj/mknative/amd64/usr/src2/destdir.amd64/usr --with-gmp=/var/obj/mknative/amd64/usr/src2/destdir.amd64/usr --enable-tls --disable-multilib --disable-symvers --disable-libstdcxx-pch --build=x86_64-unknown-netbsd5.99.56 --host=x86_64--netbsd 

Thread model: posix 

gcc version 4.5.3 (NetBSD nb2 20110806) 
COLLECT_GCC_OPTIONS='-v' '-O2' '-fno-strict-aliasing' '-I' '/usr/pkg/include/' '-o' 'a.out' '-L' '/usr/pkg/lib/' '-mtune=nocona' '-march=x86-64' 
/usr/libexec/cc1plus -quiet -v -I /usr/pkg/include/ barefoot.cpp -quiet -dumpbase barefoot.cpp -mtune=nocona -march=x86-64 -auxbase barefoot -O2 -version -fno-strict-aliasing -o /var/tmp//cc9Dcmwi.s 
GNU C++ (NetBSD nb2 20110806) version 4.5.3 (x86_64--netbsd) 
     compiled by GNU C version 4.5.3, GMP version 5.0.2, MPFR version 3.0.1-p4, MPC version 0.9 

GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=131007 
#include "..." search starts here: 
#include <...> search starts here: 
/usr/pkg/include/ 
/usr/include/g++ 
/usr/include/g++/backward 
/usr/include/gcc-4.5 
/usr/include 
End of search list. 

GNU C++ (NetBSD nb2 20110806) version 4.5.3 (x86_64--netbsd) 
     compiled by GNU C version 4.5.3, GMP version 5.0.2, MPFR version 3.0.1-p4, MPC version 0.9 
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=131007 
Compiler executable checksum: a34e7d170f4dd8d4687d2b62e8dca4b7 
In file included from /usr/include/g++/bits/gthr.h:166:0, 
       from /usr/include/g++/ext/atomicity.h:34, 
       from /usr/include/g++/bits/ios_base.h:41, 
       from /usr/include/g++/ios:43, 
       from /usr/include/g++/istream:40, 
       from /usr/include/g++/fstream:40, 
       from barefoot.cpp:29: 
/usr/include/g++/bits/gthr-default.h:130:9: error: 'pthread_detach' was not declared in this scope 
/usr/include/g++/bits/gthr-default.h:130:1: error: invalid type in declaration before ';' token 
/usr/include/g++/bits/gthr-default.h: In function 'int __gthread_detach(pthread_st*)': 
/usr/include/g++/bits/gthr-default.h:668:46: error: '__gthrw_pthread_detach' cannot be used as a function 
In file included from /usr/pkg/include/boost/regex/v4/regex_workaround.hpp:25:0, 
       from /usr/pkg/include/boost/regex/v4/regex.hpp:32, 
       from /usr/pkg/include/boost/regex.hpp:31, 
       from barefoot.cpp:32: 
/usr/include/g++/cstdlib: At global scope: 
/usr/include/g++/cstdlib:132:11: error: '::system' has not been declared 

我尝试添加-lpthread，但导致相同的输出。不知道接下来要尝试什么。

Answer 1

我不确定你为什么面临这个问题，但我可以为你提供一些下一步的尝试。

• 请注意，第一个错误是缺少pthread_detach。系统头文件通常会确保包含他们需要的任何标题，但您可以尝试在所有其他标题上添加<pthread.h>。

• 如果不成功，您需要弄清楚添加#include <pthread.h>的结果包含哪个文件，并确保其中存在pthread_detach（它确实应该在某处）。

• 假设它在那里，必须有一些条件编译导致它不能被源代码看到。找到有条件的守卫，以及哪些宏观价值影响它。

• 然后，您将需要明白为什么您的系统定义宏值的方式导致函数pthread_detach不可见。

通过此调查，您可能会发现您不包括正确的<pthread.h>文件。这可能是由于系统包含与您要使用的包含目录冲突的目录。

This answer（它朝下）this question显示了如何显示g++编译器的预定义宏。