I'm trying to help my son with a Programming C++ for Engineers course. I got him set up with Xcode 13.1 on his iMac but I've never used it myself. That was working great until his first assignment that required writing output to a file. We created a new Command Line Tool project and then used the File->New->File... option to create an Empty file. After doing so, selecting that file and looking at the info on the right side of the window shows that the Full Path is pointing to the directory where his main.cpp file is. Yet, when running his code nothing was being written to the file. I had assumed that just referencing the file name in his code would cause it to use a local reference and look in the same directory as main.cpp. After much Googling I found a reference that said to go to Product->Scheme->Edit Scheme... then select the Options tab in the window that opens and change the Working Directory from "$(BUILT_PRODUCTS_DIR)" to the directory containing the main.cpp file. That got the programming working correctly. My questions are:
Is there a preference setting that would tell it to always use the current project directory so that we don't have to change this every time?
Where does "$(BUILT_PRODUCTS_DIR)" point to?
What should we be doing differently?
I am coding a project in C++ in CodeBlocks, and I am trying to use the hashlib++ library, and I have it in my code as such:
#include <hashlibpp.h>
When I click "build and run", on that line of code I get the following error:
fatal error: hashlibpp.h: No such file or directory
I have the entire hashlib++ library in the same directory as my main.cpp file.
I was following the instructions on the documentation at http://hashlib2plus.sourceforge.net/doc/README.TXT.html
but either the instructions in sections 3.1 and 3.2 did not work or I did not follow them properly.
I would appreciate any insight as to why I am getting this error.
Ok, so I figured out what the issue was. By section 3.1,
Go to your project in the "Management" tab, and right-click the project you are working on. If you cannot see that section go to View > Manager, or press Shift + F2.
After right-clicking, select "add files..." and simply find and add the .h file you will be using. After it should show up in the "Management" section in a folder called "Headers".
Type in appropriate #include line in your code. I downloaded the entire hashlib2plus folder and put it in my project folder, so mine looked like
#include "hashlib2plus/trunk/src/hashlibpp.h"
Hope this resolves any issues in the future!
I am working on a project which requires me to open an HTML file and use its contents. I added it to Resource files but when I try to open it lie this:
std::ifstream templateFile;
templateFile.open("filename.html", std::ifstream::in);
The operation fails. I checked it by using templateFile.fail().
The above operation works when I provide the full path. The file lies in the project folder along with other files. I tried setting build action to content but still it doesnt work. Please Help.
Output directory, where your executable is compiled and put into differs from the source directory, where you create all your .cpp/.hpp files (I assume there is filename.html file). Local path filename.html is supposed to be local for your executable file, not the source file.
Read more about changing the output directory here: https://msdn.microsoft.com/en-us/library/ms165410.aspx
Under Configuration Properties / Debugging, see what your Working Directory is using the macros dialog box. Move your file into this folder.
Click the button shown in the figure. There, click either Edit or Browse. Browse will take you to the working directory. Edit will expose the link to open the macros box
My Eclipse didn't show any console outputs.
I tested the ".exe" in the debug file of my C++ project, with wich i received an error that "libgcc_s_dw2-1.dll" was missing.
I read abit on this and i found that i could simply copy/paste that file from my c:/MinGW/bin folder to the ".exe" in the "/debug" folder of my project.
That helped me with that error but i then received the message that "libstdc++-6.dll" was missing, so i did the same again.
Now The ".exe" works fine and I get an output in my eclipse.
But now i'm afraid that i will get simillar erro's at my next build if i use some what more complex programming.
I also think that it would be very timeconsuming if i have to add those files too all of my future projects.
Question:
So my question now isn't there a way to tell eclpise that those .dll files are at "c:/MinGW/bin"?
PS.
I suspect that a similar question already exists but I wouldn't have a clue on what tags I'd have to search for.
Speacial thanks to #Deniz !
right click on "my computer" => properties .
on the right select "Advanced system settings".
open "Enviormentvariables"
search for "path"
select Edit
you'll have a list of paths, hit "end" on your keyboard to make sure you are at the end of this list.
then add ";" to close the previous path and add the path to your MinGW/bin location. (by default C:\MinGW\bin).
result in adding ";C:\MinGW\bin"
I've been using windows in a class I've been taking but I am trying to run a basic code to figure out how to open/close/input/output from files on Xcode and the code I usually use on visual studios isn't working any idea why? thanks!
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
ifstream fin;
ofstream fout;
string input;
fin.open("inputFile.txt");
if(fin.fail())
cout << "File failed to open." << endl;
fin >> input;
fout.open("outputFile.txt");
fout << input;
}
Put your .txt files in the same directory where your main.cpp file is (or anywhere you like).
In Xcode go to Product > Scheme > Edit Scheme > Run (on the left) > Options (middle top)
Down under Options for "Working Directory" check “Use custom working directory” and set it to the directory where you .txt files are located.
To work with the files, you will have to specify just file names, e.g. in_file.open("inputFile.txt"); no path is necessary.
Here's a completely different approach: Have Xcode copy the input file for you.
Select your project in Xcode
Select Build Phases
Click the '+' button to create a new Build Phase
Select New Copy Files Build Phase
Select Products Directory
Click the '+' button to add your file
Click Add Other
Select your input file and click Open
Check the Copy items… checkbox and click Finish
Now every time you build your project, the input file will be copied to the same folder as the executable no matter where it is built. Of course, to see the output file, you'll still need to find the executable in Finder.
The answers don't really explain the problem so I thought I'd do that.
When you pass a relative path like "inputFile.txt" to file APIs, it's treated as relative to the working directory when the program is executed. This is the same as the 'working directory' when you use cmd.exe or Terminal.app or command lines in general. The Unix command pwd ("print working directory") displays the current working directory. On Windows running the command cd with no arguments performs the same function. (On Unix running cd with no arguments will change the working directory to the user's home directory.)
When you run a program from the command line, the command line shell sets the program's working directory. When you run a program from within an IDE, the IDE sets the working directory. Since, unlike on a command line, there's no obvious answer for what the IDE should set as the working directory, Visual Studio and Xcode set the working directory to different locations by default: Visual Studio sets the working directory to $(ProjectDir), the directory containing the Visual Studio project file; Xcode sets the working directory to the build products directory, i.e. the location the executable was written to.
Some possible solutions to your problem are:
Do not use a relative path, and therefore don't depend on the working directory. This isn't much help in making the program more portable, because the absolute paths will also differ between platforms, and so you will still have to 'configure' the program for each platform. In fact using an absolute path is worse, because it means your source code must differ, whereas it would be better to keep that difference confined to each platform's build configuration.
Configure the IDE to use your desired working directory. Visual Studio can be configured by right clicking the project, selecting Configuration Properties > Debugging > Working Directory, and setting the working directory to the desired path (potentially using Visual Studio build variables).
nepete's answer describes how to configure the working directly set by Xcode.
Configure the IDE's build process to copy your data files to an appropriate location. In Visual Studio you would do this in a C++ project by configuring the project's Properties > Configuration Properties > Build Events.
SSteve's answer covers how to configure additional build steps in Xcode.
I'm guessing you have inputFile.txt in the folder that contains your source code. That's not going to work. You need to put it in the folder that contains the generated executable. To find that folder, right-click on your app under Products and select Show In Finder.
This image shows what it looks like for a command line program. It also shows the Finder window that was opened. As you can see, it is a different folder than the one containing the source code.
As suggested by nepete, edit the scheme, but use $PROJECT_DIR as the custom working directory. Helps with moving the project around, or working in two different environments (e.g., home and office).
BTW. $PROJECT_DIR is one of the Xcode Environment Variables, and also helps with passing file names as command line arguments to programs (settable under "Arguments" in the scheme).
I've struggled with the same problem today. I wanted to add C code to my Swift project and my file pointer was always NULL.
Unfortunately, in XCode 9 for iOS app, I couldn't change the working directory. Changing Build phases didn't help me either. After 4+ hours of trial and error, that's what I've come up with finally and it works:
when copying files to XCode, I've chosen "Create groups", but I needed to choose "Create folder references":
I created a new objective-c file (.m) and copied all my C code there.
I left untouched .h files (XCode generated bridging header and my own .h file with public functions declaration). Now my project structure looked like this:
In my dict.m file in place of previous plain c fopen part:
FILE *dic = fopen("dictionary.txt", "r");
I added obj-C code:
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"dictionary" ofType:#"txt"];
FILE *dic = fopen([filePath cStringUsingEncoding: NSUTF8StringEncoding], "r");
And it works now without any problem! It's just amazing!
ps I decided to write this answer in case it will help someone like me and will save them some time. If you know how to change working directory in XCode 9 for iOS, please, leave me a comment - now I am really curious why I can't find it.