I just upgraded from Ubuntu 10 to Ubuntu 14 and now get link errors when I try to build app server that uses OpenSSL. This occurs only on functions related to multithreading support e.g., CRYPTO_num_locks(). These functions still exist in the /usr/include/openssl headers, but seem not to be in the libraries I have. I installed via:
apt-get install libcurl4-openssl-dev
#define OPENSSL_THREAD_DEFINES
#include <openssl/opensslconf.h>
results in OPENSSL_THREADS being defined, which is supposed to mean the libraries support.
The solution was to add -lcrypto to the gcc linker command line. I guess these functions got moved to their own library at some point, or something else was letting the linker find them on Ubuntu 10. I have to thank RedHat for pointing this out. It produced same error as ubuntu gcc, but with additional suggestion to add libcrypto.so to the command line.
Related
I am trying to install the MPI FFTW2 libraries (fftw2.1.5) as I need them for a program that only works with that version. The specific library I need is "drfftw_mpi.h" so I try the followed:
./configure --enable-mpi --enable-type-prefix
But it always gives me the following error:
configure: error: couldn't find mpi library for --enable-mpi
In a previous question they solve it by running sudo ldconfig before, but for me it does not work giving the same error. For other mpi software they solve it in this post by passing mpicc as the right compiler to ./configure, with the CC flag CC=mpicc, something that does not work for me.
I have installed Open MPI version 4.0.3 on a Ubuntu 20.04 LTS, and when --enable-mpi is not used I was able to install "dfftw.h" "drfftw.h" "fftw.h" and "rfftw.h", do you have an idea of what I am doing wrong or what should I do to install "drfftw_mpi.h"?
I'm trying to install this project: https://github.com/drufat/triangle. Unfortunatly, I get the following error:
error: Cygwin gcc cannot be used with --compiler=mingw32
I'm using the lastest version of gcc for Cygwin on Windows 7 64 bit and I'm trying to install that project for python 3.7.1. It's seems to come from my distutil configuration. My distutils.cfg file contains:
[build]
compiler=mingw32
I tried that solution but it doens't helped:
https://stackoverflow.com/a/16740123/5075502
The gcc options to build for MinGW64 is no longer supported by the regular cygqin compiler gcc, aka x86_64-pc-cygwin-gcc. Instead, you should also install the mingw64-x86_64-gcc-core package which provides the GCC for Win64 toolchain (C, OpenMP). This will also install other packages (through dependencies) which provide compatible binutils, headers, libraries, and runtime.
In your Makefile or compiler command line, replace gcc with x86_64-w64-mingw32-gcc. This will allow you to compile and link executables which do not depend on the cygwin1.dll.
A similar problem occured. I fixed it by changing mingw32 by gcc like #phd said.
I have a problem using Paho MQTT client in C.
I downloaded the pre built binaries for my system (Windows 10 64) from their projects page. I unpacked the zip file to a folder in the documents folder, where I also created a .c file with the example at the bottom of the Paho product page. My editor is atom and my compiler is gcc.
When I tried to compile it in Atom, I got this error:
undefined reference to MQTTClient_create'
So I went searching and found plenty of topics, but I still couldn't figure out, how to resolve this issue. From this stackoverflow topic I gather that it's a linker problem and that I need to link the files during compile, so here's what I tried:
gcc MQTT.c -L "C:\Users\Pete\Documents\MQTT on C\Examples\Paho\lib" -l paho-mqtt3c
Which still gives me the same undefined reference error. When I try to link to the dll of the same name, the compiler does not find the file.
Can anyone point me in the right direction, please?
Any help is appreciated!
I'd be interested to know if you have registered the Paho MQTT dll in Windows?
You should have paho-mqtt3c.dll as part of the download.
I don't know if this will work for you, but I have the same issue (undefined reference to MQTTClient_create)...
Copy the dll file into c:/windows/system32
Run CMD Prompt as Administrator and type:
regsvr32 i/ paho-mqtt3c.dll
Worth a try.
The problem was that I was compiling the program with the 32-bit gcc compiler for the 64-bit library. Installing and using MinGW64 worked.
I had the same issue in OS X. This is how I resolved it
I compiled the paho-mqtt library in Linux/EC2 instance.
Installed all the dependencies:
sudo yum install install build-essential gcc make cmake cmake-gui cmake-curses-gui
sudo yum install cmake
sudo yum install doxygen graphviz
cmake -DPAHO_WITH_SSL=TRUE -DPAHO_BUILD_DOCUMENTATION=FALSE -DPAHO_BUILD_STATIC=TRUE -DPAHO_BUILD_SHARED=FALSE -DPAHO_MQTT_C_PATH=../paho.mqtt.c/ -DPAHO_MQTT_C_LIB=../paho.mqtt.c/src/libpaho.mqtt3as-static.a
make
make html
make install
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/ec2-user/paho.mqtt.c/src
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH
sudo ldconfig
gcc test1.c -o test1 -lpaho-mqtt3c
Compiled successfully..
./test1
This solution works for OS X as well. Replace step 2 with
brew install cmake doxygen openssl-devel
Working with embedded C-projects. There are libraries, include files and so on - for micro controllers. No need for me to use GCC for a host machine and OS (Linux Mint 64 bit). As a rule...
But now I'm trying to compile mspdebug project from a Github - with a GCC of course. And I get an error at the very begin of make:
mspdebug$ make
cc -DUSE_READLINE -O1 -Wall -Wno-char-subscripts -ggdb -I. -Isimio -Iformats -Itransport -Idrivers -Iutil -Iui -DLIB_DIR=\"/usr/local/lib/\" -o util/btree.o -c util/btree.c
util/btree.c:19:20: fatal error: assert.h: No such file or directory
#include <assert.h>
^
compilation terminated.
I search for the includes in all possible paths (I've got the list of them via gcc -v command) - there are no assert.h file, as well, as stdio.h and so on. Except virtual box directories there is only one place (where GCC does not search includes): /usr/lib/syslinux/com32/include
AFAIK, all standard libs and includes are installed with the GCC. So I try to reinstall GCC (4.8.4) - nothing changes.
What is the normal way to give GCC all standard environment it needs?
Thanks to the right direction set by Sam Varshavchik I found the info in the stackoverflow. So I did the following:
1) installed build-essential:
sudo apt-get install build-essential
2) installed libusb (since my try to build the package revealed the absence of usb.h):
sudo apt-get install libusb-dev
And it is OK! The mspdebug (v.023) is compiled and successfully tested!
So, Linux Mint 17.2 (at least) requires installing some libs to a GCC, the most basic is build-essential.
assert.h is not part of gcc, it's a part of glibc.
Most likely, your Linux distribution puts the system headers into a separate package that you need to install.
Fedora, for examples, puts the header files in the glibc-headers package. However, you can't be using Fedora, because Fedora's gcc package has a dependency on glibc-headers, to make sure that it gets pulled in.
Whatever Linux distribution you're using, you need to research which distribution package will install the system header files you need to build stuff with.
I've cross-compiled the bulk of my 32-bit code on my x64 Ubuntu install, but I can't work out how to do the same trick with libcurl.
I've tried many permutations of --host and/or --build i486, x86, etc. but none have helped. I've also tried editing the makefiles to include gcc's -m32 flag manually, but it never shows up when I run them.
What should I be doing?
After you download and extract the libcurl source package, as a root user, run this command for setting up the build environment.
configure --host=i686-pc-linux-gnu CFLAGS=-m32 CC=/usr/bin/gcc
followed by
make
you can find the libs under ./lib/.libs/libcurl.so from where you ran the make command.
if you dont find /usr/bin/gcc, you will have to install gcc for 32-bit cross compilation env in a 64-bit machine.
It would help if you gave us an error message. I've had issues on Ubuntu x64 systems compiling 32-bit code with 'ld' errors.. I solved it by adding LDEMULATION=elf_i386 to my environment.