C++ gmp和homebrew

Question

我在Mac上,我已安装gcc并gmp通过homebrew.

为了测试我的安装,我从这里尝试了一个简单的例子:

#include <iostream>
#include <gmpxx.h>
using namespace std;
int
main (void)
{
mpz_class a, b, c;

a = 1234;
b = "-5678";
c = a+b;
cout << "sum is " << c << "\n";
cout << "absolute value is " << abs(c) << "\n";

return 0;
}

首先,如果我试着g++ test.cpp -lgmpxx -lgmp抱怨

test.cpp:9:19: fatal error: gmpxx.h: No such file or directory
 #include <gmpxx.h>
                   ^
compilation terminated.

所以我试过了 g++ test.cpp -lgmpxx -lgmp -I/usr/local/include/

ld: library not found for -lgmpxx
collect2: error: ld returned 1 exit status

那我就试过了 g++ test.cpp -lgmpxx -lgmp -I/usr/local/include/ -L/usr/local/lib/

Undefined symbols for architecture x86_64:
  "operator<<(std::basic_ostream<char, std::char_traits<char> >&, __mpz_struct const*)", referenced from:
      std::basic_ostream<char, std::char_traits<char> >& operator<< <__mpz_struct [1], __mpz_struct [1]>(std::basic_ostream<char, std::char_traits<char> >&, __gmp_expr<__mpz_struct [1], __mpz_struct [1]> const&) in ccPugkZ3.o
      std::basic_ostream<char, std::char_traits<char> >& operator<< <__mpz_struct [1], __gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> >(std::basic_ostream<char, std::char_traits<char> >&, __gmp_expr<__mpz_struct [1], __gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> > const&) in ccPugkZ3.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

有趣的是,如果我评论出来的线条,cout并尝试g++ test.cpp -lgmpxx -lgmp -I/usr/local/include/ -L/usr/local/lib/ && ./a.out没有投诉.特别是这条线c = a+b;不需要被注释掉,所以我觉得似乎正在发生一些事情.

我错过了什么？如何编译示例代码？

编辑:

按照@Will的建议,我试过了 g++ test.cpp -lgmpxx -lgmp -I/usr/local/include/ -L/usr/local/lib/ -m32

ld: warning: ld: warning: ignoring file /usr/local/lib//libgmpxx.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/lib//libgmpxx.dylibignoring file /usr/local/lib//libgmp.dylib, file was built for x86_64 which is not the architecture being linked (i386): /usr/local/lib//libgmp.dylib

Undefined symbols for architecture i386:
  "operator<<(std::basic_ostream<char, std::char_traits<char> >&, __mpz_struct const*)", referenced from:
      std::basic_ostream<char, std::char_traits<char> >& operator<< <__mpz_struct [1], __mpz_struct [1]>(std::basic_ostream<char, std::char_traits<char> >&, __gmp_expr<__mpz_struct [1], __mpz_struct [1]> const&) in ccrPv2wC.o
      std::basic_ostream<char, std::char_traits<char> >& operator<< <__mpz_struct [1], __gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> >(std::basic_ostream<char, std::char_traits<char> >&, __gmp_expr<__mpz_struct [1], __gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> > const&) in ccrPv2wC.o
  "___gmpz_abs", referenced from:
      __gmp_abs_function::eval(__mpz_struct*, __mpz_struct const*) in ccrPv2wC.o
  "___gmpz_add", referenced from:
      __gmp_binary_plus::eval(__mpz_struct*, __mpz_struct const*, __mpz_struct const*) in ccrPv2wC.o
  "___gmpz_clear", referenced from:
      __gmp_expr<__mpz_struct [1], __mpz_struct [1]>::~__gmp_expr() in ccrPv2wC.o
  "___gmpz_init", referenced from:
      __gmp_expr<__mpz_struct [1], __mpz_struct [1]>::__gmp_expr() in ccrPv2wC.o
      __gmp_expr<__mpz_struct [1], __mpz_struct [1]>::__gmp_expr<__gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> >(__gmp_expr<__mpz_struct [1], __gmp_unary_expr<__gmp_expr<__mpz_struct [1], __mpz_struct [1]>, __gmp_abs_function> > const&) in ccrPv2wC.o
  "___gmpz_set_si", referenced from:
      __gmp_expr<__mpz_struct [1], __mpz_struct [1]>::assign_si(long) in ccrPv2wC.o
  "___gmpz_set_str", referenced from:
      __gmp_expr<__mpz_struct [1], __mpz_struct [1]>::operator=(char const*) in ccrPv2wC.o
ld: symbol(s) not found for architecture i386
collect2: error: ld returned 1 exit status

如果我正确理解错误消息,似乎这些库确实是为64位构建的,甚至声明mpz_class a, b, c也无法编译-m32.

Answer 1

根据这个答案，尝试运行xcode-select --install.

在 mac 上，g++ (clang) 默认无法搜索 /usr/local/include 和 /usr/local/lib