On an almost default install of Ubuntu 11.04 I installed clang.
I am trying to compile this:
#include <cstdlib>
int main(){
return 0;
}
g++ can deal with it just fine, but clang++ errors out: fatal error: 'cstdlib' file not found
Can someone explain why this happens? and what needs to be done to make this work?
I expected clang++ to be a drop-on replacement for g++.
Seems like your clang build is not searching the correct platform include paths. Try checking with
clang -v ...
where it is looking for headers (and check that your platform include paths are there). You might have to add additional include directories (e.g. /usr/include/c++/x.y).
You might want to take a look at the source file lib/Frontend/InitHeaderSearch.cpp, The method AddDefaultCPlusPlusIncludePaths does some distribution/gcc-version specific magic (I had to fix it for my own system once).
Related
I am new to MacOS, I've always written code on Linux. I was used to compiling C files with gcc, simply like
gcc -o file file.c -lm -lgsl
where here I assumed the code to contain among its includes
#include <math.h>
#include <gsl/gsl_rng.h>
Of course the library gsl is correctly installed on my Mac via homebrew, and so are pkg-config and "Command line tools", but still when I try to compile file.c I get an error message,
fatal error: 'gsl/gsl_rng.h' file not found
#include <gsl/gsl_rng.h>
^~~~~~~~~~~~~~~
The problem is not specific to gsl (I tried for instance with the library fftw3 and got the same result).
I've seen tons of people with the same kind of problems on new M1 Macs; I've read that gcc on Mac is really "clang", and different rules apply. A ton of mocking answers were suggesting to add the correct library paths to the makefile or the like. But actually I've never before felt the need for a makefile on Linux, and surely I don't want to start adding cflags and paths whenever I compile a code (I'm working on several machines with different operating systems, with my code stored on Cloud servers, so I assume I should write a makefile for each of them? Really?).
Has anyone found a proper fix?
I just started using MinGW for Windows. When trying to create executable using
g++ a.cpp -o a.exe -std=c++14
for the code below:
#include <string>
using namespace std;
int main()
{
string x = to_string(123);
return 0;
}
I'm getting following error:
C:/mingw/bin/../lib/gcc/mingw32/5.3.0/../../../libmingwex.a(vsnprintf.o):(.text+0x0): multiple definition of vsnprintf
C:\Users\..\Local\Temp\cc4sJDvK.o:c:/mingw/include/stdio.h:426: first defined here
collect2.exe: error: ld returned 1 exit status
What is the root cause for this error and how can I make it go away? While I can easily find a replacement for to_string() function I'm not sure what is causing this error to occur in the first place.
Installing MinGW packages mingw32-libmingwex-* will link an appropriate version of vsnprintf and avoid the linker error.
This issue, i.e. multiple definition of vsnprintf, still exists in MinGW as December 2019.
After investigating a lot, I found the solution in the official mailing list.
It's a bug in mingwrt-5.2.2. Downgrading to the mingwrt-5.2.1 version solves that issue.
To do that, just input the following command:
mingw-get upgrade mingwrt=5.2.1
Then restart the MinGW shell.
Read the full story here.
Note: MinGW-w64 and MinGW are separate projects, so the accepted solution is not so helpful to me, as I want to keep MinGW and not to move to MinGW-w64.
I solved this issue using MinGW w64 compiler
download mingw-w64-install.exe
setup to Version: 6.3.0, Architecture: i686, Threads: posix, Exception: dwarf and Build revision: 2.
I hope this will be of some help.
There are multiple definitions of vsnprintf in both stdio.h and libmingwex.a. I am able to work this around by adding #define __USE_MINGW_ANSI_STDIO 0 to the start of the code, before any includes, which disables the definition of vsnprintf in stdio.h.
I am relatively new to Linux and Clang, and I am having trouble getting the Clang 3.4 toolchain to correctly determine where the libstdc++ libraries are. I am running Mint 17, have Clang-3.4 installed and have GCC 4.8 installed as well.
Using the verbose flag, the output looks like:
#include "..." search starts here:
#include <...> search starts here:
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/x86_64-linux-gnu/c++
/usr/local/include
/usr/bin/../lib/clang/3.4/include
/usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
test.cpp:1:10: fatal error: 'iostream' file not found
#include <iostream>
The search stops one subfolder shy of where it looks like all the libstdc++ headers live (in /c++/4.8). I have used the package manager to uninstall and reinstall gcc, clang, llvm and all dependencies. I have also tried reinstalling using the cli using apt-get.
A majority of the answers I've seen for this question revolve around changing the /FrontEnd/InitHeaderSearch.cpp file to look in the correct place for the libstdc++ stuff, but this doesn't exist on my machine. Rather, locate -b InitHeaderSearchdoes not find any results.
Aside from building clang and llvm from source, how else can I change where clang is looking for the libraries?
Thank you.
This is puzzling me...
I have a code that looks like this:
#include <stdio.h>
#include <pbs_ifl.h>
int doSomeStuff()
{
char *server_name;
int c;
server_name = pbs_default();
c = pbs_connect(server_name);
printf("pbs_errno %d\n",pbs_errno);
// do some stuff
pbs_disconnect(c);
}
When I compile it with:
gcc -static -o executablename sourcefile.c -ltorque
It works allright, compiling with '-static'. pbs_errno is 0 and I can do my stuff.
But if I remove the '-static' flag it starts giving me this message when I run it:
munge: Error: Unable to access "/var/run/munge/munge.socket.2": No such file or directory
So... I start the munge service (munged) and it stops complaining about it, but instead I get pbs_errno=15033 and can't get anything from the cluster (do my stuff).
Any ideas?
I don't know if I delete de question or answer it, but it seems so be solved... so I'm posting the solution here.
I had 2 versions of the lib installed, one via yum other via source.
Since only the compiled code had the static libs, when I was linking -static gcc was linking with the compiled code and when I was linking dynamic it was linking with the yum version.
I just had to enforce the linking with the right libs adding the following flag when liking:
-Wl,-rpath=/usr/local/lib
I'm really a Python developer exclusively, but I'm making my first foray into C programming now, and I'm having a lot of trouble getting started. I can't seem to get the hang of compilation and including libraries. At this point, I'm just identifying the libraries that I need and trying to compile them with a basic "hello, world" app just to make sure that I have my environment setup to do the actual programming.
This is a DBus backend application that will use GIO to connect to DBus.
#include <stdlib.h>
#include <gio/gio.h>
int
main (int argc, char *argv[])
{
printf("hello, world");
return 0;
}
Then, I try to compile:
~$ gcc main.c
main.c:2:21: fatal error: gio/gio.h: No such file or directory
#include <gio/gio.h>
I believe that I've installed the correct packages as indicated here, and gio.h exists at /usr/include/glib-2.0/gio/gio.h.
I found a command online to add a search directory to gcc, but that resulted in other errors:
~$ gcc -I /usr/include/glib-2.0/ main.c
In file included from /usr/include/glib-2.0/glib/galloca.h:34:0,
from /usr/include/glib-2.0/glib.h:32,
from /usr/include/glib-2.0/gobject/gbinding.h:30,
from /usr/include/glib-2.0/glib-object.h:25,
from /usr/include/glib-2.0/gio/gioenums.h:30,
from /usr/include/glib-2.0/gio/giotypes.h:30,
from /usr/include/glib-2.0/gio/gio.h:28,
from main.c:2:
/usr/include/glib-2.0/glib/gtypes.h:34:24: fatal error: glibconfig.h: No such file or directory
#include <glibconfig.h>
^
compilation terminated.
There has to be some relatively simple method for being able to set some options/variables (makefile?) to automatically include the necessary headers. I'm also going to use Eclipse-CDT or Anjuta as an IDE and would appreciate help to fix the import path (or whatever it's called in C).
Any help is greatly appreciated.
Use pkg-config (and make). See exactly this answer to a very similar question. See also this and that answers. Don't forget -Wall -g flags to gcc ..
You don't need an IDE to compile your code (the IDE will just run some gcc commands, so better know how to use them yourself).