I have tried to include openssl (I try to implement a ssh client) and I've added libssl.dylib to my Xcode Project. But I don't know which header I have to include to use it.
Can anyone show me a tutorial how to use libssl in Xcode?
thanks
There is nothing special about OpenSSL regarding includes, it is in the standard SDK and you include the header-files you need from openssl/*, e.g.:
#include <openssl/bio.h>
Related
If you build C++14 code with G++ and libstdc++, there's a library named libstdc++fs, which is separate from the rest of libstdc++, and contains the code for std::experimental::filesystem. If you don't link against it, you'll get undefined references.
The "trick" I'm using for overcoming this right now is:
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
set(CXX_FILESYSTEM_LIBRARIES "stdc++fs")
endif()
and later:
target_link_libraries(my_target PUBLIC ${CXX_FILESYSTEM_LIBRARIES})
but - I don't like having to place this code in every project I work on. Is there a simpler or more standard idiom I could use? Some way this will all happen implicitly perhaps, with some CMake behind-the-scences magic?
tl;dr: Nothing right now, wait for a newer CMake version
As #Pedro graciously points out, this is a known problem, and there is an open issue about it at KitWare's GitLab site for CMake:
Portable linking for C++17 std::filesystem
If using CMAKE_CXX_STANDARD=17 and std::filesystem, GCC requires linking of an extra library: stdc++fs. ... If C++17 is enabled, would it be worth automatically linking to stdc++fs for GCC versions which require this? Likewise for any quirks in other compilers or libraries.
The KitWare issue is about C++17, for which apparently you still need the separate extra library (i.e. it's not just because of the "experimentality" in C++14). Hopefully we'll see some traction on this matter - but
Note: If you're experiencing this problem with C++17's std::filesystem, you're in luck - that code is built into libstdc++ beginning with GCC 9, so if you're using g++ 9 or later, and std::filesystem, you should no longer experience this problem.
What I'm doing I'm developing an R interface/package for C++ codes with Rcpp and CMake. Because openmp and c++11 should be supported, so I have a preference on compilers.
Problem I know that I can always put Makevars under ~/.R (Unix) to change the compiler R uses when install packages. But as a developer, it is not recommended to do so.
It is recommended to use configure file to do that. However, I don't quite know how to achieve this, because I'm writing configure file by myself and calling cmake inside my configure. I don't know what to write in configure file to search for a specific compiler.
Hope the description is clear. Thank you.
I have attached my configure file content below.
```
set -x
set -e
which cmake
rm -rf _builds
# call cmake that will set compiler flags in src/Makevars
# and download dependencies
cmake -H. -B_builds
```
I've been using CMake for building R packages for quite a while, see https://github.com/rohan-shah/mpMap2 for an example.
I completely bypass the R build system though, so I don't use configure at all.
As I understand, you want to detect if the compiler supports openmp and C++11.
There are many existing packages using configure to detect openmp support. One example is ARTP2 (https://github.com/zhangh12/ARTP2/blob/master/configure.ac), which has been mentioned in the "Writing R extension" as an example. You can also use the configure script in xgboost by me (https://github.com/dmlc/xgboost/blob/master/R-package/configure.ac) as an example. We leave OPENMP_CXXFLAGS blank if the compiler doesn't support openmp.
For C++11 support, you can try AX_CXX_COMPILE_STDCXX_11. But this will require a new version of autoconf.
I think you can also try AC_PROG_CXX to select compilers, like icc.
I am using Qt-Creator on Mac OS X for C++-development (I don't use Qt itself). The strange thing is, that Qt-Creator is unable to find any files that are directly in /usr/inlcude. Everything still compiles, but I just cannot use features like autocomplete or "Follow symbol under cursor" in Qt-Creator because of that.
So for C++ headers like iostream, everything works as expected, it finds the header files and indexes them correctly. But if I want to use something from unistd.h, Qt-Creator does not find the include directory. I am using clang 5.2 (from Apple) and Mac OS X 10.9.2.
I even tried adding this (redundant) line to my CMakeLists.txt file:
include_directories(/usr/include)
but that does not help. It is nothing I can not live with, but it is still frustrating.
So I found the problem (it is really stupid). I decided to start Qt Creator from the command line. By doing so, I saw error messages from clang which complained about unknown/wrong arguments and this helped me to find the problem. It is IMHO kind of bad that you never see those in the GUI...
So to make C++11 work correctly, I had to go to settings->Build & Run -> Compilers and make a copy of clang and add "-std=c++11 -stdlib=libc++" to the codegen flags. I made a stupid typo there and wrote "-std=c++11 -stdlib=c++" instead. Since Qt Creator still found all header from libc++ and had c++11 activated, I never bothered to double check this. But changing this flag to the correct one did the trick.
EDIT: Just want to add: I found it extremely strange, that Qt Creator was able to find ALL include files (I use several third party libraries at several different locations - no problem there) EXCEPT for those in /usr/include if you screw up these compiler flags.
I am new to C++ and plugin development. I am working with/for Unix and for the Firefox browser. So here we go:
I have a plugin which uses some classes from a own library. The problem is: it kills my browser asap. I cant even start my browser as soon as MyPlugin.so is in the plugin folder of the Firefox. The library is build and doesn't kill a desktop application that uses it.
My guess is that I failed at linking my library with CMake or forgot to include some stuff from FireBreath. So here are the two things I assume are wrong, maybe someone can help me out.
1) (wrong?) linking with Cmake:
I added some of these at the end of the CMakeLists.txt of my project. The paths are where the library is.
add_definitions(-L${CMAKE_CURRENT_SOURCE_DIR}/../../../lib/bin)
add_definitions(-I${CMAKE_CURRENT_SOURCE_DIR}/../../../lib/src)
add_definitions(-lcoala64) [name of the library]
add_definitions(-Wl,-rpath=${CMAKE_CURRENT_SOURCE_DIR}/../../../lib/bin)
add_definitions(-pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/harfbuzz -lgtk-x11-2.0 -lgdk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lcairo -lpango-1.0 -lfreetype -lfontconfig -lgobject-2.0 -lglib-2.0)
And used the prepmake.sh to generate my build files. Then I followed up with adding flags manually (because I dont know a better solution) to the in the /buid/projects/MyPlugin/CMakeFiles/MyPlugin.dir/link.txt
-L/home/username/swp/dev/lib/bin
-I/home/username/swp/dev/lib/src
-lcoala64 -Wl,-rpath=/home/username/swp/dev/lib/bin
Afterwards I could build the plugin. It builds, so one could assume I have linked correctly. But said crashes appear as soon as I want to use it.
2) Do I use the library wrong?
I include like this in MyPluginAPI.h:
#include <string>
#include <sstream>
#include <boost/weak_ptr.hpp>
#include <boost/smart_ptr.hpp>
#include "JSAPIAuto.h"
#include "BrowserHost.h"
#include "X11/X11KryptoKoala.h"
//Include from my own library:
#include "../../../lib/src/Key.hpp"
As soon as I add the following line to MyPlugin.cpp I get the mentioned crashes while the same line works without a problem in the desktop application that uses the same library:
Key key(password_);
Now I hope this isn't a too big wall of text and someone is willing to investigate and answer to me.
You shouldn't use add_definitions() in that way. CMake allows to differentiate your directives in different categories, so that they only go in the necessary command line. You should use:
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread")
include_directories(/usr/include/gtk-2.0
/usr/include/cairo
etc. etc.
)
add_library(the_name_of_your_target gtk-x11-2.0 gdk-x11-2.0 ETC. ETC.)
link_directories(${CMAKE_CURRENT_SOURCE_DIR}/../../../lib/bin)
Furthermore, there are FindPackage functionalities that can help you setting automatically variables containing the name of your libraries, their directories, their include path.
Most information can be found here and here
Then: What is then prepmake.sh? Are you running cmake at all? Can you use cmake-gui, and then select one canonical build system, like make or ninja?
Finally: It could be that you have a crash because your library are not in your library path. I assume you are under linux, here are some ideas: LD_LIBRARY_PATH vs LIBRARY_PATH and LD_LIBRARY_PATH
Is there an Objective-C syntax checker?
I have tried gcc -fsyntax-only but it is not really 'syntax only'. It still produces errors if run on an individual implementation file which has references to external frameworks.
I am looking for something that can perform a syntax check on individual header or implementation files without attempting to link or produce object files.
Can gcc do this with additional flags I am unaware of, or is there another tool up to this task?
I want to do this from the command-line. Can xcodebuild do this for an individual file? Running xcodebuild for the entire project to check the syntax of one file is a bit much.
There's no way for it to check the syntax without it knowing about the header files for the frameworks you are using. You need to use the -framework flag to include the relevant header files.
You could try using clang -fsyntax-only instead, especially if you're using 10.6/Xcode 3.2. Clang/LLVM has much better separation between the parser and the other parts of the compiler chain. You can find clang in /Developer/usr/bin.
So after trawling through the gcc man page I discovered the -F flag which lets you add a framework directory to the list of directories gcc searches for header files.
This solves my issue.
Use it like this: gcc -fsyntax-only -ObjC -F/Path/To/A/Framework -F/Path/To/Another/Framework File.m
You can compile a single file in Xcode[1] using Build->Compile (cmd-K) which is effectively a syntax check (there's no linking step).
[1] I assume you're using Xcode, as there's little point in using Objective-C without OS X (really the Cocoa frameworks).