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b-ak
Asked: 2012-07-31 09:43:07 +0800 CST

Trouble with aliases and opencv

  • 772

I have an alias defined to compile an opencv program which goes like this

alias gcv='g++ -I/usr/local/include/opencv -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_objdetect'

Then I go on to type 

gcv imageshow.cpp

I get this long list of errors

enter image description here

But when I use the same command specified in the alias with the .cpp(source code) file in between the Include and Library files (following the suggestion here), everything works like a charm.

g++ -I/usr/local/include/opencv imageshow.cpp -lopencv_core -lopencv_imgproc -lopencv_highgui

Now typing the long command, which gets even bigger as complexity increases, every time is getting difficult, please help me in getting the alias to work or suggest any other alternative.

command-line

3 Answers

  1. Best Answer

    Try this without using aliases:

    g++ imageshow.cpp -o imageshow `pkg-config --cflags --libs opencv`
    • 3

  2. Why not use a simple script instead of the alias?

    file gcv in ~/bin/

    #/bin/sh 
g++ $* -I/usr/local/include/opencv -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_objdetect

    Alternatively if you're using zsh you can use a function defined in your .zshrc file:

    gcv() { 
    g++ $* -I/usr/local/include/opencv -lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_objdetect;
}

    Automated compiler and linker flags

    If you're having linker issues, you can also incorporate pkg-config here:

    #/bin/sh 
g++ $* `pkg-config --cflags --libs opencv`

    Spaces in filenames

    While other posts on similar issues exist, handling spaces in the filenames is not trivial so I thought I'd recap an elegant solution here; specifically I found that making use of the IFS variable helps tremendously.

    So making a small addition to end up with 

    #/bin/sh 
IFS=$';'
g++ $* `pkg-config --cflags --libs opencv`

    solves issues with spaces in filenames too!

    • 0

  3. The post on creating a shell script wasn't very clear .. This was the simple procedure I followed to create a script of my own and it works even if the filename have spaces in it..

    Here's what I did

    • mkdir ~/bin
    • nano ~/bin/gcv
    • sudo chmod u+x ~/bin/gcv

    • Type in the following into the script

          #!/bin/bash   
    g++ "$@" `pkg-config --libs --cflags opencv`

    • export PATH=$PATH:~/bin

    • Type echo $PATH and make sure u see ~/bin listed in the output u get.
    • Type alais if you see any aliases by the name gcv use the command unalias gcv or else u'll have trouble using gcv as a command to compile the code, May be aliases have higher priority than scripts.
    • Even if my file-names have spaces in them the script won't have an issue.
    • 0