c ++无法找到包含

Question

Just installed build-essentinals in debian 7. But i noticed the includes for c++ are in /usr/include/c++/4.7... Does anyone why? Includes used to be in /usr/include, as far as I remember...

Everything fails now... ie

main.c:2:20: fatal error  iostream: No such file or directory

And even if i include it with -I, headers are called from headers and it won't find anything, like:

/usr/include/features.h:323:26: fatal error: bits/predefs.h: No such file or directory

So beacuse bits is NOT in /usr/include but in /usr/include/c++/4.7 compiler can't find it...

I'm using g++

crafter# g++ -o craft main.cpp 
In file included from /usr/include/c++/4.7/x86_64-linux-gnu/bits/os_defines.h:40:0,
                 from /usr/include/c++/4.7/x86_64-linux-gnu/bits/c++config.h:414,
                 from /usr/include/c++/4.7/iostream:39,
                 from main.cpp:2:
/usr/include/features.h:323:26: fatal error: bits/predefs.h: No such file or directory

compilation terminated.

Anyone knows how to fix this?

Thanks for your help!

Answer 1

You are using gcc to compile C++ code, which results in C++ system headers not being considered in the header lookup process. Use g++ command instead.

Also, you should rename main.c to main.cpp since you are using C++ features.

Finally, compiling a .cpp file with gcc will clear the preprocessing and compiling phase, but fail the linking, because libstdc++ will not be implicitly added.

Your command line should look like g++ main.cpp -o outname .

Answer 2

Apparently a 32/64 bit mixup . Solved by installing libc6-dev-i386 for 32 bits builds, or by building for 64 bits.

Answer 3

A stated by Stefano Sanfilipo, there was indeed a mixup with 32 and 64 bit libraries.

I solved as suggested by removing all dev packages:

apt-get remove --purge libc6-dev
apt-get remove --purge libc6-dev-i386

And then reinstalling:

apt-get install build-essential

And now it compiles perfectly.

MSalters also saw the problem though, what shold I do in this case so that both get credit?

Regards,

David

Answer 4

只需将include directlory放在编译器的-I参数中，例如：

$(CC) -I/usr/include/c++/4.7 ...