变量具有不完整的类型 std::string；string.h 有很多错误

Something is very wrong with strings. I have been using them for weeks without issue, but halfway through Monday, I started having strange issues:[Clang IntelliSense] Error: variable has incomplete type 'std::string'whenever I try to make a string. similar errors occur when I try wstring and ostringstream, but not stringstream. initializing std::string* s also works fine but s->append(...) results in"member has access into incomplete type 'std::string'"This all came about because visual studio (VS) was all of a sudden unable to find some #includes that I have had for weeks, including some standard libraries (don't remember which because...). I solved that by having VS search for the correct files and it found some files (unsure if they're the same as before or different) so it no longer has an issue with the #include statements but now I have this issue.I had been using <string.h> fine for weeks. while researching this issue, I read that <string.h> is the wrong file to use so I've tried #include <string> but there is no difference. I've since tried <strings.h> and <cstring> but no difference there either.I checked out my external dependencies and string.h has dozens of errors, which I thought is weird because it's a standard file that I haven't touched.I'm using VS2015, GNU make, and I see Clang IntelliSense but I also see some g++ here so I'm not sure what compiler it's actually using. also using visualGDB 5.3. let me know if I forgot anything.#include <iostream>#include <string>#include <sstream>int main(int argc, char *argv[]){std::string message = "uncomment";...messageis the part that is highlighted as having an issue (incomplete type)std::wstring wideMessage;also incomplete typeexpected results: no problems like the past few weeks. I was able to declare, initialize, append(), whateveractual results: can't compile/debugerrors: variable has incomplete type 'std::string' variable has incomplete type 'std::wstring' no matching constructor for initialization of 'std::ostringstream'I see many similar issues here, but all the issues have to do with forward declaration and I don't see what that has to do with this. I'm not having any issues with classes, structs, or functions; even declaring a variable in main() is problematicedit: based on this answer, it is likely using VC++ 14.0 as a compiler but I do not know how to tell for sureedit 2: error message:1> VisualGDB: Sending 45 updated source files to build machine...1> VisualGDB: Run "make CONFIG=Debug" in directory "/tmp/VisualGDB/c/Users/pthien/VS/Whatever/Whatever" on pthien@buildserver (SSH)1> /opt/poky/1.8/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-g++ -march=armv7-a -mfloat-abi=hard -mfpu=neon -mtune=cortex-a8 --sysroot=/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi -ggdb -ffunction-sections -O0 -std=c++11 -march=armv7-a -mfloat-abi=hard -mfpu=neon -mtune=cortex-a8 --sysroot=/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi -ggdb -ffunction-sections -O0 -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include -I/opt/googletest-master/googletest/include -I/opt/boost_1_61_0 -I../../cereal/cereal-1.2.2/cereal-1.2.2/include -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/websocketpp-master -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/websocketpp -I/opt/curl-7.54.0 -I/opt/boost_1_61_0/boost -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/easywsclient-master -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/uWebSockets-master -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/c++/4.9.2/experimental -I/opt/boost_1_61_0/boost/tr1/tr1 -I/opt/boost_1_61_0/tools/build/src/engine -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/c++/4.9.2 -I/opt/curl-7.54.0/include -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/cereal -I/opt/poky/1.8/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/4.9.2/include-fixed -I/opt/boost_1_61_0/boost/compatibility/cpp_c_headers -I"../../../../../Program -IFiles -I(x86)/Microsoft -IVisual -IStudio -I10.0/VC/crt/src" -I"../../../../../Program -IFiles -I(x86)/Microsoft -IVisual -IStudio -I14.0/VC/include" -I/opt/poky/1.8/sysroots/cortexa8hf-vfp-neon-poky-linux-gnueabi/usr/include/c++/4.9.2/arm-poky-linux-gnueabi -DDEBUG -c Whatever.cpp -o Debug/Whatever.o -MD -MF Debug/Whatever.dep1> C:\Users\pthien\AppData\Local\VisualGDB\RemoteSourceCache\buildserver\0008\include\wchar.h(459,20): note : 'wcstold'1> extern long double wcstold (const wchar_t *__restrict __nptr,1> ^1> Whatever.cpp: In function 'int main(int, char**)':1>C:\Users\pthien\VS\Whatever\Whatever\Whatever.cpp(138,47): error : 'strlen' was not declared in this scope1> size_t request_len = strlen(webSocketRequest);1> ^1> Makefile:160: recipe for target 'Debug/Whatever.o' failed1> make: *** [Debug/Whatever.o] Error 11> -------------------------------------------------------------1> Command exited with code 21> Executable: make1> Arguments: CONFIG=Debug1> Directory: /tmp/VisualGDB/c/Users/pthien/VS/Whatever/Whatever1>VisualGDB : error : Command-line action failed1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Microsoft.MakeFile.Targets(37,5): error MSB3073: The command ""C:\Program Files (x86)\Sysprogs\VisualGDB\\VisualGDB.exe" /build "C:\Users\pthien\VS\Whatever\Whatever\Whatever.vcxproj" "/solution:C:\Users\pthien\VS\Whatever\Whatever.sln" "/config:Debug" "/platform:Win32"" exited with code 1.========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========This is about 10% of the output, including the beginning and the end. What's weird is the issue with strlen(). It is not underlined in the IDE, so I had no idea there was an issue with it. It makes sense because I commented out the #include for <string.h>and <cstring> and strlen() is in one of those. 解决方案 managed to avoid this issue, but probably not solve the still-unknown underlying issue, by removing an unused library from my list of directories and then reloading all directories. I'm not convinced anything was solved because reloading directories gives random results. sometimes it fixes issues and sometimes it causes new ones. Just yesterday, I reloaded and it was then unable to find system.h and time.h (don't remember the names). I was troubleshooting that but the issue disappeared a few hours later. anywayI posted a follow-up question here 这篇关于变量具有不完整的类型 std::string；string.h 有很多错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！