Resently I'm installed Opencv in my machine. Its working in python well(I just checked it by some eg programs). But due to the lack of tutorials in python I decided to move to c. I just run an Hello world program from http://www.cs.iit.edu/~agam/cs512/lect-notes/opencv-intro/
while compiling I got the following error
hello-world.c:4:16: fatal error: cv.h: No such file or directory
compilation terminated.
I'm new in opencv
Qn : Could you please report what may be the problem - and how I run my helloworld program in c?
Your compiler cannot find your cv.h include file. If you installed from your package manager, it is probably in /usr/include/opencv/. You need to add that your include search path. If you are compiling from the command line use -I to specify additional include directories. It will be something like -
gcc -I /usr/include/opencv/ -o helloworld helloworld.c
If you are using Eclipse,
Right click on the project and select properties.
Select C/C++ General -> Path and Symbols.
Select Includes tab.
In Languages list, select 'GNU C' or 'GNU C++' depending on which you are using.
Press 'Add...' button and add /usr/include/opencv/
Save and rebuild.
You need to show compiler path to cv.h file. The quick way to find it is to do (on Ubuntu):
find /usr -name "cv.h"
/usr/local/include/opencv/cv.h
Just add this to the compiler:
gcc -I/usr/local/include/opencv -o helloworld helloworld.c
Since you asking this question your compiler might also have problems linking your program to opencv libraries. Just do the same thing only for library files:
find /usr -iname "libopencv*"
/usr/local/lib/libopencv_flann.so
...
add this folder the same way and specify libraries you want to use:
gcc helloworld.c -I/usr/local/include/opencv -L/usr/local/lib -lopencv_core -lopencv_imgproc -lopencv_highgui -o helloworld
that should probably compile. There is a also a short cut you can take and instead of all that steps just use the following command
gcc helloworld.c `pkg-config --cflags --libs opencv` -o helloworld
that should take care of all the work of locating required files for you and let you focus on the fun coding part.
maybe you just installed the opencv package.
But, as you want to use opencv in your C program, you may also install the package named just like opencv-devel. If you haven't, install it and than use it as #iagreen said.
Best wishes to you.
Related
kplot is a UNIX programming library for plotting graphs on a Cairo surface. The source code is available here.
After downloading the source code I extraced it to the directory kplot-master and cd into it. Simple ls now shows
array.c
border.c
bucket.c
buffer.c
....
example0.c
example1.c
....
I am using Ubuntu 14.04 LTS. Cairo is installed in my system and I tested it by successfully compiling C codes available in [zetcode dot com slash gfx slash cairo slash cairobackends slash] (Sorry as I am not allowed to link more than two).
I am new to GTK and Cairo plotting library and would like help in the following directions:
I do not want to install kplot in my system.
I just want to learn how kplot uses Cairo.
When I use the following command:
gcc example0.c -o example `pkg-config --cflags --libs gtk+-3.0`
it produces the following error message:
example0.c:17:20: fatal error: compat.h: No such file or directory
#include "compat.h"
^
compilation terminated.
It will be very helpful if somebody shows me how to test those kplot examples without installing it.
There is no need to install.
First you will need to compile the kplot library. For that, cd to the kplot directory and run a make command. This will generate the file compat.h. After that you will be able to compile example by example with make example(n) command, or with gcc example(n).c -o example(n) `pkg-config --cflags --libs gtk+-3.0` libkplot.a -lbsd -lm command.
If you have GTK+-3.0 and Cairo dev libraries installed, everything should go well.
I am trying to install and use pocketsphinx on ubuntu in c language but I keep getting this error
/Desktop/Programming/C/Tests$ gcc libraries.c -o libraries
libraries.c:2:26: fatal error: pocketsphinx.h: No such file or directory
#include <pocketsphinx.h>
^
compilation terminated.
I have followed the step required to install sphinxbase and pocketsphinx found here but I keep getting the error every time I compile my code. Is there something i missed?
How did you install pocketsphinx? and what do you mean by "installing"
To work with a library you first need to have the headers in place where your compiler can find them (for GCC for example by using the -I option) and then you need to have the library installed so your compiler can build against it.
Judging from the error you didn't specify the header files of the library to your compiler
You can add manually
First go to the includes folder
$ cd /usr/include
Then add the pocketsphinx.h manually
$ sudo ln -s /my/path/to/pocketsphinx.h
So then when you want to include pocketsphinx.h file, you can use:
#include <pocketsphinx.h>
I'm trying to use liboauth with a C program, using gcc as my compiler, and no matter what I've tried I keep getting the error "ld: library not found for -loauth" and "clang: error: linker command failed with exit code 1".
I'm including the header via "#include <oauth.h>", and my most-recent call to gcc looked like this:
gcc -Wall -lcurl -loauth -I /usr/local/include -v -o api api.c
Now, oauth.h does exist in /usr/local/include, and there are a handful of liboauth files (including liboauth.a) located in /usr/local/bin, which I'm assuming were placed there when I ran the install. I will admit that I'm not very familiar with gcc and compiling non-trivial C programs, but I was able to get libcurl working on a fresh download in just a few minutes. I just can't figure out what's going on with liboauth.
Thanks in advance
If you are sure liboauth's located in /usr/local/bin use
gcc -Wall -L/usr/local/bin -I /usr/local/include -v -o api api.c -lcurl -loauth
It'd also be better to place libraries in the end of the command as there is some important stuff with them (they may depend on each other, etc).
By the way, it's pretty strange your libraries are in /usr/local/bin as libraries are almost always stored in some path like /usr/*/lib.
I am trying to compile the simple C example from this tutorial on Ubuntu using GCC. What do I have to use as arguments for GCC to include the needed libraries for #include <libappindicator/app-indicator.h>?
-I<search path to include files>
-L<search path to the lib file>
-l<libname>
Use the -l command line option. You can specify the library search path with the -L option. E.g:
gcc -o myprogram -lfoo -L/home/me/foo/lib myprogram.c
This will link myprogram with the static library libfoo.a in the folder /home/me/foo/lib.
If you used apt-get, Synaptic Package Manager, etc. to get the appindicator library (vs. building it from source), did you only install the libappindicator1 package or did you also install libappindicator-dev to get the libappindicator header files? Linux packages very often have split the runtime libraries from the compile-time headers. That way people who only need the libraries to satisfy a dynamic link don't have to install unneeded headers. But since you're doing development you need those headers and therefore need the libappindicator-dev package as well.
What I do is:
pkg-config --list-all | grep indicator
Use:
gcc example.c -o example `pkg-config --cflags --libs appindicator-0.1`
pkg-config will fetch the required include and library flags for libappindicator and its dependencies. This assumes libappindictaor-dev package is already installed.
You are trying to make a GTK app, and the previous solutions are as applicable anywhere like using the -l option and -I option,
However, for GTK applications, you may also use pkg-config which makes it easier as your paths can be predefined.
An interesting example can be found in
http://developer.gnome.org/gtk/2.24/gtk-compiling.html
I have install the C/C++ CDT Version of Eclipse. After making a HelloWorld.c file and get the code in there I get an error of "Launch failed. Binary not found".
I found in google that my Eclipse miss the compiler and I install MinGW on my computer and add the path to env variables (tested it with "gcc -v" in cmd and succeded).
1) I can build now, but have no idea how to make a MAKEFILE. - I Read 10 tutorials but don't understand it - ideas?
2) I can build, but not run, I get "Launch failed. Binary not found" - ideas?
Found the error: I never maked a ".c" file -.- after renaming it - works fine.
Revised answer: If you want to avoid writing a real makefile, you can write something like this:
all:
gcc *.c -o runme.exe
You need to specify the binary which gcc outputs (gcc [..] -o <this one>) in the run settings (in the previous example, it should point to runme.exe). Go to Run->Run Configurations, and under C/C++ Application browse and look for runme.exe.
I would, however, strongly advise you to seriously learn about makefile. The beauty of makefiles is that you can use very little features at first and use more and more as you go on (as you saw, writing a "dummy" file was very quick). At first I suggest you write something a bit more "clever" than what I gave you above. Here's a nice tutorial and an example:
all: hello
hello: main.o factorial.o hello.o
g++ main.o factorial.o hello.o -o hello
main.o: main.cpp
g++ -c main.cpp
factorial.o: factorial.cpp
g++ -c factorial.cpp
hello.o: hello.cpp
g++ -c hello.cpp
clean:
rm -rf *o hello
all is what compiles at default. What comes before the : are rule names and after it are the dependencies. i.e, to compile all you need to compile hello (though only if it's been updated), and so forth. the line below the rule is the command to compile. I hope this helps. Please read the tutorial, Makefiles are important.
Add the directory that gcc resides in (C:\MinGW\bin or whatever) to your PATH environment variable and restart Eclipse (important!). This is the process in XP: http://vlaurie.com/computers2/Articles/environment.htm. That should sort it out.
1 I suggest you to take a look at this:
http://www-scf.usc.edu/~csci410/handouts/make.pdf
It's a basic gmake tutorial and should be enough to get you started. But right now, for single file project, I suggest you to just skip creating Makefiles and doing in the command prompt:
gcc -o helloworld.exe helloworld.c
And running your executable in the prompt. You can worry about Makefiles later in your learning curve.
2 How did you setup your project?
Make sure you've got a binary parser selected when you bring up properties for the project. At least in my install, none were checked by default. I needed to check Mach-O 64 parser; you'll need to pick one based on what you're doing. I picked this up from http://www.thexploit.com/tools/os-x-10-6-64-bit-eclipse-cdt-missing-binaries/
I didn't have a binary parser selected, and that seems to mean that CDT can't find anything that it recognizes as a binary. It meant in my case that I just got the "Launch failed. Binary not found" message, even though I specified the exact binary, including a fully-qualified path, in the run/debug configurations.
This has nothing to do with builds, just running/debugging. If you're having a problem building, this probably is irrelevant.