I recently installed include-what-you-use (IWYU) to try it out. I am on version include-what-you-use 0.12 based on clang version 9.0.1-10. (My OS is Ubuntu 20.04 on WSL1)
I tried to do a very simple example on a source code file, but it quickly comes back as an error on the very first include? (Which is just a c standard library file)
After running
include-what-you-use myutils.cpp:
In file included from myutils.cpp:8:
In file included from ./myutils.h:11:
/usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/cfloat:42:10: fatal error: 'float.h' file not found
#include <float.h>
^~~~~~~~~
Why is it error'ing out on a c standard library include?
I cannot post the entire source here, and without extensive testing I am not sure what minimal example would cause this problem.
Am I just mis-using IWYU? I installed it via apt rather than building it and llvm/clang/etc from scratch. Is that fine?
I am running a fresh install of Linux Mint 20.1 and I'n trying to compile a program for a GPS tracker, but it won't compile:
In file included from /usr/include/c++/9/bits/stl_algo.h:59,
from /usr/include/c++/9/algorithm:62,
from /usr/include/x86_64-linux-gnu/qt5/QtCore/qglobal.h:142,
from /usr/include/x86_64-linux-gnu/qt5/QtCore/QtCore:4,
from pch.h:27:
/usr/include/c++/9/cstdlib:75:15: fatal error: stdlib.h: No such file or directory
75 | #include_next <stdlib.h>
| ^~~~~~~~~~
compilation terminated.
I have installed a number of additional libraries (libusb, libmarble and a few others) and qmake.
Of course, stdlib.h is present on the system:
$ find /usr -name stdlib.h
/usr/include/x86_64-linux-gnu/bits/stdlib.h
/usr/include/bsd/stdlib.h
/usr/include/stdlib.h
/usr/include/c++/9/tr1/stdlib.h
/usr/include/c++/9/stdlib.h
/usr/include/tcl8.6/tcl-private/compat/stdlib.h
After looking at the other questions about this, I re-installed build-essential, which didn't help.
I re-installed the g++ compiler, no luck either.
I copied /usr/include/c++/9/stdlib.h to /usr/local/include, but it still complains about a missing stdlib.h
I changed the
#include_next <stdlib.h>
in cstdlib into
#include <stdlib.h>
only to find that the next include cannot find stdlib.h; changing that one produced the third include and so on. So that does not work either.
The program compiles and works on Slackware 14.2 by the way.
What am I missing?
Hello-world compiles normally; a simple program that does a malloc also compiles and runs.
I used to #anastaciu 's solution.
As it was a fresh install without much customization, I resorted to the option of a complete re-install. Bizarre that that works a bit, as it was already a fresh install. I still had to copy stdlib.h and a few others (math.h etc.) to /usr/local/lib` to get to the point where it would at least compile.
I am working on a c++ project using mosquitto library on github. I am trying to compile the C++ on a windows computer on the command line; however I keep getting error
Fatal error: mosquitto.h: no such file or directory
include "mosquitto.h"
I have installed the mosquitto library in the windows system, underneath:
C:\Program Files\mosquitto\devel\mosquitto.h
Is there something else that I have to do as well in order to compile the cpp from the command line. How do I tell g++ the whereabout of the mosquitto.h file. So I can compile on the command line
Thank for your help I am new to C++.
I managed to solve this question, I had o copy the mosquitto.h into
C:\cygwin64\usr\include
Then when I type g++ nameOfFile it compiled
I have been trying to use Matlab compiler SDK to packaging my Matlab program as C++ shared library in Debian system. I have got the folder including test.c, test.h, test.so (test is my Matlab program name), and I have installed the Matlab_runtime in the Debian system. I have set the variables LD_LIBRARY_PATH_ and _ XAPPLRESDIR_ as required in the readme.txt _ *( _ replace MCR_ROOT by the directory where the MATLAB Runtime is installed on the target machine.
(1) Set the environment variable XAPPLRESDIR to this value:
MCR_ROOT/v91/X11/app-defaults
(2) If the environment variable LD_LIBRARY_PATH is undefined, set it to the concatenation of the following strings:
MCR_ROOT/v91/runtime/glnxa64:
MCR_ROOT/v91/bin/glnxa64:
MCR_ROOT/v91/sys/os/glnxa64:
MCR_ROOT/v91/sys/opengl/lib/glnxa64_)*
.
I edit my main.cpp include test.h. when I try to compile the main.cpp use _ gcc main.cpp -o main_, I got the error as follows:
In file included from main.cpp:2:0:
test.h:15:22: fetal error: mclmcrrt.h: No such file or directory
#include "mclmcrrt.h"
I know that mclmcrrt.h is in the package of Matlab_runtime, it means I failed to link to the library of Matlab_runtime. Anybody knows what should I do to make my main.cpp compile successfully? I tried two days to work on how to connect to the Matlab_runtime library, but still failed. I am a beginner to linux. Great thanks if anyone can help.
This is a compilation problem, not linkage. Your compiler does not know where mclmcrrt.h is. Please help it find it by telling it where it is:
gcc -I<the_folder_where_mclmcrrt.h_lives_in> ...
Whenever I try to compile this code it always ends up with this error:
In file included from /usr/include/wchar.h:6:0,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/cwchar:44,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/bits/postypes.h:40,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/iosfwd:40,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/ios:38,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/ostream:38,
from /usr/lib/gcc/i686-pc-cygwin/4.9.2/include/c++/iostream:39,
from test.cpp:1:
/usr/include/sys/reent.h:14:20: fatal error: stddef.h: No such file or directory
#include <stddef.h>
^
compilation terminated.
The code I was trying to compile is:
#include <iostream>
using namespace std;
int main()
{
cout << "Hello World! :D";
return 0;
}
The error is because your gcc-core package and gcc-g++ are not of the same version. Either downgrade one of them to solve the problem or update both the libraries. Updating both the libraries is the recommended way.
I had this error on a fresh MinGW install, it had nothing to do with the installed packages mentioned in the current accepted answer by "Prasanth Karri". In my case the issue was caused by -nostdinc in my Makefile. I actually only needed that compiler flag when building for a different target platform (not when using MinGW) so I fixed the issue by removing that flag from MinGW builds.
When I was incorporating a software library written in C into an existing demo project(used a C++ mbed library) I encountered this problem. The demo project would compile just fine, but after I replaced the existing main file by my own, this error occurred.
At this point I hadn't yet thought about the fact that the mbed library that I needed was written in C++. My own main file was a .c file that #include the mbed header file. As a result I used my normal C source as if it was a C++ source. Therefore the compiler that was used to compile my main file was the C compiler.
This C compiler then encountered a #include of a module that actually does not exist (within its scope), as it's not a C++ compiler.
Only after I inspected the output of the build log I realised the various source C and C++ files were compiled by more that 1 compiler(the c++ compiler). The project used used compilers arm-none-eabi-c++ and arm-none-eabi-gcc (for embedded systems) as seen below.
Compile log:
Building file: ../anyfile.cpp
Invoking: MCU C++ Compiler
arm-none-eabi-c++ <A lot of arguments> "../anyfile.cpp"
Finished building: ../anyfile.cpp
Building file: ../main.c
Invoking: MCU C Compiler
arm-none-eabi-gcc <A lot of arguments> "../main.c"
In file included from <Project directory>\mbed/mbed.h:21:0,
from ../main.c:16:
<Project directory>\mbed/platform.h:25:19: fatal error: cstddef: No such file or directory
compilation terminated.
Of course in a C++ environment cstddef exists, but in a C environment cstddef doesn't exist, in stead it's just C's implementation of stddef.
In other words, cstddef does not exist in the C compiler.
I resolved this problem by renaming my main.c file to main.cpp and the rest of the code compiled smoothly too.
TLDR/Conclusion: When building a C++ project, avoid mixing C files with C++ files(sources and headers). If possible rename .c files to .cpp files to use the C++ compiler in stead of the C compiler where required.
In order to update it, follow below.
If you are on Windows, just run these on command prompt or powershell
Update the package list: mingw-get update
After updating the package list, run: mingw-get upgrade
Source: How to update GCC in MinGW on Windows?
This problem was solved for me as I installed codeblocks with mingw compiler then I copied the mingw folder from codeblocks to C drive and added
C\mingw\bin to the environment variables.
If you try to compile and see a message like, "fatal error: stddef.h: No such file or directory", the error is because your gcc-core and gcc-g++ packages are not of the same version. Rerun the Cygwin install and make sure that you select the highest numbered versions of gcc-core and gcc-g++.
After installing the C++ compiler with MinGW I encountered this problem as well. Apparently, you have to also install mingw32-base. Go to C:/MinGW/bin/mingw-get.exe (my path) and check it for installation at the Basic Setup tab.