I am trying to process a binary file generated by a PSI DRS4 for work. I tried this using a C++ code given in the src folder of the software used to run the board.
A friend of mine compiled and executed this code on his linux computer just fine. I wanted to adapt this code to windows. I went through the compilation step pretty easily but then when I try to execute it, it just crashes...
After some further investigation, what I understand is that the header(s) cannot be read properly (probably leading to the crash when they're supposed to be used later in the code)
I thus tried to read the file with HexEditor Neo and here is what I get: screenshot binary file Hexeditor
As you see the part after EHEADER becomes unreadable... Is it normal? Has anyone faced this situation before ?
Related
I have compiled a mex file using MATLAB. I am having trouble since every time I try to run the code, MATLAB crushes.
I have tried using feval() function with a mexhost in order to separate the processes and debug, following this guide. When I am executing using feval(mh,'functionName',input), all I am getting is:
Invalid C++ MEX-file 'test_c'
However, when I am executing using feval(mh,functionName,input) I am getting an nrhs of size 0.
I have followed throw with this guide and used the DependancyWalker utility to get the following result:
A lot of the DLLs are missing. Even the basic LIBMEX.DLL can't be found. Am I doing something wrong here? How do I debug?
Probably some of MATLAB's folders aren't in your system path variable (%PATH% on Windows).
I have developed a ShinyApp that is built around a C++ program. In short, what the app does is :
provides a nice interface to setup the parameters (in a text file) for the C++ app
runs the C++ compiled code using the system(...) command
displays the output of the C++ code using ggplot2
The C++ compiled code is stored into the www folder. Locally it works fine, but when I load the app to the shinyapp website (I have a free subscription), I got the following error:
sh: 1: ./a.out: Permission denied
with a.out being my compile c++ code. Any idea if
I am doing something wrong?
It is possible call a compiled c++ code within shinyapp.io?
This is a super old question, but since I stumbled on it looking for an answer for my identical problem, I would share what worked for me.
I didn't try the .bat suggestion mentioned in the comments, because that seemed to be tied to Windows OS and Shiny uses Linux.
Instead, I used R's Sys.chmod() function. In your case, if you are calling system("a.out"), before that line, put Sys.chmod("a.out", mode="777"). Note that you may want to look more into what chmod does with regards to permissions. But the code would look like:
// ...
Sys.chmod("a.out", mode="777")
system("a.out")
// ... remaining code
p = subprocess.Popen([executable_file])
This is only code that I am using to run the python subprocess. However, it has unknown issue that cause my program cannot open the executable file as expected.
executable_file is one file link (PATH) that locate executable program.
Ex. C:\Users\SharkIng\Dev\WhatEverSystem\Builds\Windows\program-123456789-123456789.exe
The python subprocess.Popen should run the program. However, sometime it works and sometime it is not (I did not change any code between this two situation)
OS: Windows 10
Python: 2.7.*
Error: [Error 2] The system cannot find the file specified
BUT: It is working if you manually run subprocess.Popen([executable_file_path_string]) (with same file and path) it work.
WHY this happen?? Is that because some problem with Windows Python? or it is because my setting mess me up?
UPDATE: It is not some reason such as NOT FULL PATH. I can have it working with exact same code. If I ran same code in a python shell, by typing each line of code. It works. But if I put exact same code in a .py file and run it with python file.py, it showing the error
UPDATE 2: Another team member have same error with Windows 7 and Python 2.7.* This code used to work this morning. AGAIN I didn't change anything. That is way I am asking if it is unstable.
There is no problem with subprocess. If you want to run a specified executable, you need to give the full path to that file. The most likely reason you're seeing variable behavior is that sometimes you're in the directory with the .exe, and other times you're not.
I have recently started coding with C++ and I have come across a little source of error which I think requires knowledge about computers that I don't have.
When I write a simple code (in Visual Studio Express 2013), let's say a "Hello World!" example, I Build and Start Without Debugging successfuly.
Then, when I edit my code to print the sum of two numbers for example, I get an error when I try to Build. I get this error:
Error 1 error LNK1168: cannot open c:\users\name\documents\visual
studio 2013\Projects\ConsoleApplication4\Debug\ConsoleApplication4.exe
for writing
But if I wait for a bit and then re-attempt to Build, everything is fine.
I have also noticed this when I use g++ in the standard cmd module; if I try to complile a code under the same name (for the .exe file) I get an Access Denied error, but if I wait a bit I am allowed to do it.
My instincts tell me that the computer still has the .exe file running for a bit after I execute it, and it is not allowing me to overwrite it.
It's because the process is still running and therefore the file is in use and write-locked. It takes Windows a few tempo beats to clean everything up after you've terminated.
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.