Question

为了尝试从NDK 15c过渡到NDK16b，我遇到了编写遗留代码的障碍，该代码试图将64位长的值写入ostream。

我已经搜索了NDK头文件，在std/_ostream中我觉得如果定义了#ifdef _STLP_LONG_LONG，那么ostream运算符应该支持我尝试做的事情。< / p>

我无法看到启用此功能需要做什么。我尝试用-D_STLP_LONG_LONG来定义它无济于事。

我的工具链正在使用NDK中的clang编译器。

这是实际的编译器输出：

MyInfo.cc:6499:33: error: use of overloaded operator '<<' is ambiguous (with operand types 'basic_ostream<char, std::char_traits<char> >' and 'long long')
      os << basename << ":" << (long long) val;
      ~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:104:10: note: candidate function
_Self& operator<<(unsigned char __x) { _M_put_char(__x); return *this; }
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:106:10: note: candidate function
_Self& operator<<(short __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:107:10: note: candidate function
_Self& operator<<(unsigned short __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:108:10: note: candidate function
_Self& operator<<(int __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:110:10: note: candidate function
_Self& operator<<(unsigned int __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:117:10: note: candidate function
_Self& operator<<(long __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:118:10: note: candidate function
_Self& operator<<(unsigned long __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:123:10: note: candidate function
_Self& operator<<(float __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:124:10: note: candidate function
_Self& operator<<(double __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:126:10: note: candidate function
_Self& operator<<(long double __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:130:10: note: candidate function
_Self& operator<<(bool __x);
     ^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:304:1: note: candidate function [with _Traits = std::char_traits<char>]
operator<<(basic_ostream<char, _Traits>& __os, char __c) {
^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:297:1: note: candidate function [with _CharT = char, _Traits = std::char_traits<char>]
operator<<(basic_ostream<_CharT, _Traits>& __os, char __c) {
^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:311:1: note: candidate function [with _Traits = std::char_traits<char>]
operator<<(basic_ostream<char, _Traits>& __os, signed char __c) {
^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_ostream.h:318:1: note: candidate function [with _Traits = std::char_traits<char>]
operator<<(basic_ostream<char, _Traits>& __os, unsigned char __c) {
^
/Users/spartygw/android-toolchain/bin/../lib/gcc/arm-linux-androideabi/4.9.x/../../../../include/c++/4.9.x/stl/_iomanip.h:96:1: note: candidate function [with _CharT = char, _Traits = std::char_traits<char>]
operator<<(basic_ostream<_CharT, _Traits>& __os,
^

Answer 1

_STLP_LONG_LONG是STLPort macro。如果您确实在使用STLPort，则可能需要编辑NDK中的文件stl_mycomp.h。

但是，由于STLPort only supports C++98并且从NDK r16开始不推荐使用，因此您应该使用libc ++（在NDK之前，r16 gnustl也可能是一个选项）。

Android NDK16错误（＆＃34;运算符＆＃39;＆lt;＆lt;＆＃39;是不明确的（操作数类型＆＃39; basic_ostream <char，std :: char_traits <char =“”>＆gt;＆＃39 ;＆＃39; long long＆＃39;）＆＃34;

1 个答案: