I'm pretty new to c++, as in I'm still learning the basic of it
anw. I want to use pcre in it, but have so far been unsuccessful in getting it to work.
I'm running Ubuntu and have in my latest attempt tried to install the libpcre3-dev package (I should mention that I am rather new to Linux too)
I included pcre with
#include <pcrecpp.h>
currently I'm getting the error "undefined reference to pcrecpp::RE::no_arg" whenever I try to define an RE object
pcrecpp::RE reg("fys|smi|int|fok|arv|kar");
Can anyone explain to me what I'm doing wrong, and or give me a step by step guide on how to do it.
And I do know that c++ have a regex library, but since I'm used to pcre from php, that is what I'm going for
You should pass -lpcrecpp on the command line to link your program with the PCRE library. Just including the declarations in a header file is not enough.
Related
I know how to code but I really do not know my way around a computer.
I have a program that I have to run for my master thesis. It is a code with multiple collabs and runs perfectly on Linux. However, it is a very complex simulational code and therefore it takes time to run for multiple parameters. I've been using my Linux at the university to run it but would like to run some of it on my personal computer (MAC OS). It works by using the R language to call upon c++ functions as follows (being filename a code on c++).
On a Rstudio script:
Sys.setenv("PKG_CPPFLAGS" = "-fopenmp -DPARALLEL")
system("rm filename.so")
system("rm filename.o")
system ("R CMD SHLIB filename.cpp")
dyn.load("filename.so")
After system ("R CMD SHLIB filename.cpp") I get error:
clang: error: unsupported option '-fopenmp'
make: *** [filename.o] Error 1
I've researched on the subject and found this
Enable OpenMP support in clang in Mac OS X (sierra & Mojave)
I've Installed LLVM, yet I do not know how to use it in this case.
How do I use it in this case?
Thank you in advance.
"Don't do it that way." Read up on R and Rcpp and use the proper tools (especially for packaging and/or compiling) which should pick up OpenMP where possible. In particular,
scan at least the Rcpp Introduction vignette
also look at the Rcpp Attributes vignette
"Just say no" to building the compilation commands by hand unless you know what you are doing with R and have read Writing R Extensions carefully a few times. It can be done, I used to show how in tutorials and workshops (see old slides from 12-15 years ago on my website) but we first moved to package inline which helps here, and later relied on the much better Rcpp Attributes.
Now, macOS has some extra hurdles in which tools work and which ones don't. The rcpp-devel mailing list may be of help, the default step is otherwise to consult the tutorial by James.
Edit: And of course if you "just want the above to work" try the obvious step of removing the part causing the error, i.e. use
Sys.setenv("PKG_CPPFLAGS" = "")
as your macOS box appears to have a compiler but not OpenMP (which, as I understand it, is the default thanks to some "surprising" default choices at Apple -- see the aforementioned tutorial for installation help.)
I have been trying to compile a basic tensorRT project on a desktop host -for now the source is literally just the following:
#include <nvinfer.h>
class Logger : nvinfer1::public ILogger
{
} glogger;
Upon running make, though, I receive the following message:
fatal error: nvinfer.h: No such file or directory #include <nvinfer.h>
The error is correct, too - I used locate to try to find it, but there's nothing on my machine that matches. I followed the install instructions for desktop installation of TensorRT 2.1 as described here: https://developer.nvidia.com/nvidia-tensorrt-download
So my question is, does anyone know where nvinfer.h is supposed to be? In other words, am I missing a needed package that contains it, or did I miss something else that's essential?
Small addendum: one thing I noticed is that libgie1 is not installed, and it was not included as a debian with the provided TensorRT download like the other packages such as gie-dev were.
Before using locate, if you recently added new files is a good practice to run sudo updatedb, if the file is on the pc you should see it after.
Anyway googling a bit it looks like the header your looking for is NvInfer.h, caps matters.
My goal is to create a package in R with C++ code: So my questions is how?
I am following the tutorial http://www.stat.columbia.edu/~gelman/stuff_for_blog/AlanRPackageTutorial.pdf on creating an R package containing C++ code. The specific code Im trying to compile and package is exactly as described in the tutorial.
R CMD SHLIB seems to be working creating .dll file.
I can load in R using dyn.load() and test it on simulated data (as described in tutorial)
R CMD INSTALL is where the problem begins. I have done two things encountering two different errors supposedly related:
1) The tutorial says the NAMESPACE file is supposed to contain the code:
useDynLib(XDemo)
export(XDemoAutoC)
When it does R CMD INSTALL fail resulting in error:
Error in inDL(x,as.logical(local), as.logical(now),...): unable to
load shared object 'C:/.../libs/i386/XDemo.dll': Loadlibrary failure:
1% is not a valid Win32-program
2) Removing the above mentioned lines in NAMESPACE file will result in installation of package. I can succesfully load it in R but when I try to use the R function that makes a .C() call to the C++ written function I another error:
library(newpackage)
ls(package:newpackage)
[[1]] "XDemoAutoC"
Warning message:
In ls(package:newpackage) :
‘package:newpackage’ converted to character string
XDemoAutoC(c(1,2,3,4))
Error in .C("DemoAutoCor", OutVec = as.double(vector("numeric", OutLength)), :
C symbol name "DemoAutoCor" not in load table
Im running version R2.15.2 on windows 64-bit and using R64 bit.
I read the following post with a similar problem:
http://r.789695.n4.nabble.com/Include-C-DLL-error-in-C-symbol-name-not-in-load-table-td3464021.html
Except they mention nothing about the NAMESPACE-matter.
Also I read this post:
Problem with loading compiled c code in R x64 using dyn.load
So I am thinking: that based on the fact that I am able to use dyn.load() in Rx64 means that I have succesfully created x64 .dll. Assuming that the NAMESPACE file is supposed to be left as in the tutorial - hopefully fixing the >>not in load table<< error - this would mean I should focus on fixing problem one. This problem seems to be caused by something related to 32-bit. I have used Dependency Walker on the .dll file but I am not sure how to interpret the results
I really don't have any ideas on how to fix this problem so any suggestion on what to do would be welcome?
I think you are doing it wrong. Two quick suggestions:
Read the Writing R Extensions manual written to explain just this: writing R extensions including those with compiled code
Have a look at Rcpp which makes R and C++ extensions, including package building so much easier. Or so we think. Writing a package is as easy as calling Rcpp.package.skeleton(). The documentation in 1) still help.
That said, if R CMD INSTALL fails you may have some mixup in your $PATH. Never ever mix MinGW and Cygwin. Make sure no Cygwin DLLs are found when you build or call R. Path order matters greatly. See the manual for details.
Currently I'm trying to start programming on my new Mac. I installed TextWrangler, and chose C++ as my language of choice; since I have some prior knowledge of it, from when I used Windows.
So, I wrote the ever so common "Hello World" program. Although, when I tried to run it, I got an error:
"This file doesn’t appear to contain a valid ‘shebang’ line (application error code: 13304)"
I tried searching the error code to find out how to fix this, but I couldn't find anything.. I have no idea what a 'shebang' line is... Can someone help me out?
You need to compile it with a compiler first. I assume you tried to run the source file like ./source but C++ doesn't work this way.
With some compilers however, you can provide a shebang-line as the first line of the source file (the #! is known as shebang or crunchbang, hence the name), like so:
#!/path/to/compiler
So that the shell knows what application is used to run that sort of file, and when you attempt to run the source file by itself, the compiler will compile and run it for you. That's a compiler-dependent feature though, so I recommend just plain compiling with G++ or whatever Macs use to get an executable, then run that.
While I wouldn't recommend it for regular C++ development, I'm using a simple shell script wrapper for small C++ utilities. Here is a Hello World example:
#if 0 // -- build and run wrapper script for C++ ------------------------------
TMP=$(mktemp -d)
c++ -o ${TMP}/a.out ${0} && ${TMP}/a.out ${#:1} ; RV=${?}
rm -rf ${TMP}
exit ${RV}
#endif // ----------------------------------------------------------------------
#include <iostream>
int main(int argc, char *argv[])
{
std::cout << "Hello world" << std::endl;
return 0;
}
It does appear that you are trying to run the source file directly, however you will need to compile using a C++ compiler, such as that included in the gcc (GNU Compiler Collection) which contains the C++ compiler g++ for the Mac. It is not included with the Mac, you have to download it first:
from http://www.tech-recipes.com/rx/726/mac-os-x-install-gcc-compiler/ : "To install the gcc compiler, download the xcode package from http://connect.apple.com/. You’ll need to register for an Apple Developer Connection account. Once you’ve registered, login and click Download Software and then Developer Tools. Find the Download link next to Xcode Tools (version) – CD Image and click it!"
Once it's installed, if you are going for a quick Hello World, then, from a terminal window in the directory of your source file, you can execute the command g++ HelloWorld.cpp -o HelloWorld. Then you should be able to run it as ./HelloWorld.
Also, if you're coming from a Visual Studio world, you might want to give Mono and MonoDevelop a try. Mono is a free implementation of C# (and other languages), and MonoDevelop is an IDE which is very similar to Visual Studio. MonoDevelop supports C# and other .NET languages, including Visual Basic .NET, as well as C/C++ development. I have not used it extensively, but it does seem to be very similar to VS, so you won't have to learn new everything all in a day. I also have used KDevelop, which I liked a lot while I was using it, although that's been a while now. It has a lot of support for GNU-style development in C/C++, and was very powerful as I recall.
Good luck with your endeavors!
Links:
Mono: http://mono-project.com/Main_Page
MonoDevelop: http://monodevelop.com/
KDevelop: http://kdevelop.org/
shebang is http://en.wikipedia.org/wiki/Shebang_%28Unix%29.
not sure why your program is not running. you will need to compile and link to make an executable.
What I find confusing (/interesting) is C++ program giving "Shebang line" error. Shebang line is a way for the Unix like operating system to specify which program should be used to interpret the rest of the file. The shebang line usually points to the path of the interpreter. C++ is a compiled language and does not have interpreter for it.
To get the real technical details of how shebang lines work, do a man execve and get that man page online here - man execve.
If you're on a mac then doing something like this on the commandline:
g++ -o program program.cpp
Will compile and link your program into an executable called program. Then you can run it like:
./program
The reason you got the 'shebang' error is probably because you tried to run the cpp file like:
./program.cpp
And the shell tries to find an interpreter to run the code in the file. Because this is C++ there is no relevant interpreter but if your file contains Python or Bash then having a line like this
#!/usr/bin/python
at the 1st line in your source file will tell the shell to use the python interpreter
The lines that start with a pattern like this: #!/.../.../.. is called a shebang line. In other words, a shebang is the character sequence consisting of the characters number sign and exclamation mark (#!).In Unix-like operating systems, when a text file with a shebang is used as if it is an executable, the program loader mechanism parses the rest of the file's initial line as an interpreter directive. The loader executes the specified interpreter program, passing to it as an argument the path that was initially used when attempting to run the script, so that the program may use the file as input data.
I'm trying to profile a C++ application, that I did not write, to get a sense for where the major computation points are. I'm not a C++ expert and even less so C++ debugging/profiling expert. I believe I am running into a (common?) problem with dynamic libraries.
I compile link to Google CPU Profiler using (OS X, G++):
env LIBS=-lprofiler ./configure
make
make install
I then run profile the installed application (jags) with:
env CPUPROFILE=./jags.prof /usr/local/bin/jags regression.cmd
pprof /usr/local/bin/jags jags.prof
Unfortunately, I get the error:
pprof /usr/local/bin/jags jags.prof Can't exec "objdump":
No such file or directory at /usr/local/bin/pprof line 2833.
objdump /System/Library/Frameworks/Accelerate.framework/Versions/A/
Frameworks/vecLib.framework/Versions/A/libLAPACK.dylib: No such file or directory
The program dynamically links to libLAPACK.dylib. So prof does not seem to understand it (?). I thought about trying to statically link, but the documents associated with the program say that it is impossible to statically link in LAPACK or BLAS (two required libraries).
Is there a way to have the profiler ignore libLAPACK? I'm okay if it doesn't sample within libLAPACK. Or how might I get profiling to work?
This error was caused by jags being a shell script, that subsequently called profilable code.
pprof /usr/local/bin/REAL_EXEC jags.prof
fixes the problem.
I don't see a clean way to do it, but maybe there's a hacky workaround -- what happens if you hack the pprof perl script (or better a copy thereof;-), line 2834, so that instead of calling error it emits the message and then does return undef;?
If you're profiling on OSX, the Shark tool is really great as well. It's very simple to use, and has worked out of the box for me when I've tried it.