‘strcmp’未在此范围内声明

Question

我正在使用此教程构建 ios 工具链。当我运行命令 make ENABLE_OPTIMIZED=1 时，我得到此输出。

llvm[0]: Reconfiguring with /home/connor/llvm-svn/configure
config.status: creating Makefile.config
config.status: creating llvm.spec
config.status: creating docs/doxygen.cfg
config.status: creating tools/llvm-config/llvm-config.in
config.status: creating include/llvm/Config/config.h
config.status: creating include/llvm/Support/DataTypes.h
config.status: include/llvm/Support/DataTypes.h is unchanged
config.status: creating include/llvm/ADT/hash_map
config.status: include/llvm/ADT/hash_map is unchanged
config.status: creating include/llvm/ADT/hash_set
config.status: include/llvm/ADT/hash_set is unchanged
config.status: creating include/llvm/ADT/iterator
config.status: include/llvm/ADT/iterator is unchanged
config.status: executing setup commands
config.status: executing Makefile commands
config.status: executing Makefile.common commands
config.status: executing examples/Makefile commands
config.status: executing lib/Makefile commands
config.status: executing runtime/Makefile commands
config.status: executing test/Makefile commands
config.status: executing test/Makefile.tests commands
config.status: executing tools/Makefile commands
config.status: executing utils/Makefile commands
config.status: executing projects/Makefile commands
config.status: executing bindings/Makefile commands
config.status: executing bindings/ocaml/Makefile.ocaml commands
make[1]: Entering directory `/home/connor/llvm-svn/lib/System'
llvm[1]: Compiling Alarm.cpp for Release build 
llvm[1]: Compiling Disassembler.cpp for Release build 
Disassembler.cpp: In function ‘std::string llvm::sys::disassembleBuffer(uint8_t*, size_t, uint64_t)’:
Disassembler.cpp:44:12: warning: variable ‘bits’ set but not used [-Wunused-but-set-variable]
llvm[1]: Compiling DynamicLibrary.cpp for Release build 
DynamicLibrary.cpp: In static member function ‘static void* llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(const char*)’:
DynamicLibrary.cpp:178:5: error: ‘strcmp’ was not declared in this scope
DynamicLibrary.cpp:178:5: error: ‘stderr’ was not declared in this scope
DynamicLibrary.cpp:179:5: error: ‘strcmp’ was not declared in this scope
DynamicLibrary.cpp:179:5: error: ‘stdout’ was not declared in this scope
DynamicLibrary.cpp:180:5: error: ‘strcmp’ was not declared in this scope
DynamicLibrary.cpp:180:5: error: ‘stdin’ was not declared in this scope
make[1]: *** [/home/connor/llvm-svn/lib/System/Release/DynamicLibrary.o] Error 1
make[1]: Leaving directory `/home/connor/llvm-svn/lib/System'
make: *** [all] Error 1

我不知道该怎么做，而且我的谷歌搜索也没有多大帮助。

Answer 1

strcmp 函数是在 string.h 中声明的，尝试放入

#include <string.h> 

DynamicLibrary.cpp 中，而 stderr 是在 stdio.h 中定义的，所以也将其放入

#include <stdio.h>

。 我时不时地发现开源代码也缺少头文件。

更新：

如果您有不同的名称，您可以搜索包含目录，

在真正的 GNU/Linux bash 中（也应该与 Windows 10 WSL 一起使用）您可以使用它来搜索函数：

find /usr/include -type f | xargs grep ' strcmp\s*\('

这用于变量：

find /usr/include -type f | xargs grep '[\s*]stdin\s*;'

在 Windows 上的 Git Bash 上有 /include 和 /mingw64/include 目录，但在我的安装中只有 ImageMagick 头文件和 /mingw64/include/gnumake.h

Answer 2

在 C++ 中编码时也会发生同样的错误。在这种情况下，请包含 cstring 库来解决该错误。

#include<cstring>