CODEWITHSUNDEEP
c++c++11clang++c++98
Aodren BARY
Aodren BARY

Reputation: 101

Clang compiles code using std::stoi in c++98 mode

I need to compile my cpp in C++98, not C++11 for my school project. So I used -std=c++98 to compile:

CPPFLAGS = -Wall -Werror -Wextra -std=c++98

but I made a mistake and use the C++11 std::stoi function.

i = std::stoi(index);

I tried without the -std=c+=98 flag but it didn't change anything. I am working on MAC 10.12.6

My code compiles without any warning or any error.

If I am not mistaken, clang should shout at me for using a C++11 function. Why?

edit clang version:

Apple LLVM version 8.1.0 (clang-802.0.42)
Target: x86_64-apple-darwin16.7.0
Thread model: posix

Upvotes: 2

Views: 1667

Answers (1)

murmur
murmur

Reputation: 53

because the -std flag is for 'language standard', 'standard library' is a separate thing. probably the compiler you are using uses libc++ standard library by default. libc++ (llvm std. lib.) still uses c++11 standard library when you get a value lower than c++11 from -std flag. libc++ is owned by llvm. if you want to use gnu standard c++ library (libstdc++) you have to use flag -stdlib=libstdc++. otherwise it uses -stdlib=libc++ by default. Using libstdc++ solved my problem. gnu c++ std. lib. supports 98 standard, llvm c++ std. lib. provides backward compatibility to 98 standard

__cplusplus value getting from -std flag (for 98 -> 199711L)

I see here that libc++ uses the 11 standard for 98

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__config

#ifndef _LIBCPP_STD_VER
#  if  __cplusplus <= 201103L
#    define _LIBCPP_STD_VER 11
#  elif __cplusplus <= 201402L
#    define _LIBCPP_STD_VER 14
#  elif __cplusplus <= 201703L
#    define _LIBCPP_STD_VER 17
#  else
#    define _LIBCPP_STD_VER 18  // current year, or date of c++2a ratification
#  endif
#endif  // _LIBCPP_STD_VER

Upvotes: 0

Related Questions