用 clang++ --std=c++11 file.cpp
编译我的程序时这条线 std::unique_ptr<FILE> pipe(popen(cmd.c_str(), "r"), pclose);
抛出错误
memdiff.cpp:11:27: error: no matching constructor for initialization of
'std::unique_ptr<FILE>'
std::unique_ptr<FILE> pipe(popen(cmd.c_str(), "r"), pclose);
^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2530:31: note:
candidate constructor not viable: no known conversion from 'int (FILE *)'
to 'const std::__1::default_delete<__sFILE>' for 2nd argument
_LIBCPP_INLINE_VISIBILITY unique_ptr(pointer __p, typename conditional<
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2537:31: note:
candidate constructor not viable: no known conversion from 'int (FILE *)'
to 'typename remove_reference<deleter_type>::type' (aka
'std::__1::default_delete<__sFILE>') for 2nd argument
_LIBCPP_INLINE_VISIBILITY unique_ptr(pointer __p, typename remove_ref...
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2547:9: note:
candidate template ignored: could not match 'unique_ptr<type-parameter-0-0,
type-parameter-0-1>' against '__sFILE *'
unique_ptr(unique_ptr<_Up, _Ep>&& __u,
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2562:35: note:
candidate template ignored: could not match 'auto_ptr<type-parameter-0-0>'
against '__sFILE *'
_LIBCPP_INLINE_VISIBILITY unique_ptr(auto_ptr<_Up>&& __p,
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2516:49: note:
candidate constructor not viable: requires 1 argument, but 2 were provided
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR unique_ptr(nullptr_t) _NOEXCEPT
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2522:40: note:
candidate constructor not viable: requires single argument '__p', but 2
arguments were provided
_LIBCPP_INLINE_VISIBILITY explicit unique_ptr(pointer __p) _NOEXCEPT
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2543:31: note:
candidate constructor not viable: requires single argument '__u', but 2
arguments were provided
_LIBCPP_INLINE_VISIBILITY unique_ptr(unique_ptr&& __u) _NOEXCEPT
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2487:29: note:
candidate constructor (the implicit copy constructor) not viable: requires
1 argument, but 2 were provided
class _LIBCPP_TYPE_VIS_ONLY unique_ptr
^
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:2510:49: note:
candidate constructor not viable: requires 0 arguments, but 2 were provided
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR unique_ptr() _NOEXCEPT
^
1 error generated.
如果我从 unique_ptr 切换到 shared_ptr,我的程序就会编译。为什么一个构造函数有效而另一个无效,我该如何解决?
最佳答案
正如第一条评论中正确指出的那样:使用 unique_ptr,必须将删除器的类型指定为第二个模板参数。
然而,它应该是一个函数指针:
std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd.c_str(), "r"), pclose);
关于c++ - unique_ptr 和指定解构函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34468712/