Cannot find -lgfortran

Question

I'm trying to install a package in R (package "ks"). It fails with error message:

/usr/bin/ld: cannot find -lgfortran

I've already installed the Ubuntu package build-essential:

sudo apt-get install build-essential

I've also tried adding symbolic links:

sudo ln -s /usr/lib/x86_64-linux-gnu/libgfortran.so.3 /usr/lib/libgfortran.so
sudo ln -s /usr/lib/libgfortran.so.3.0.0 /usr/lib/libgfortran.so
sudo ldconfig

I use gcc and g++ regularly, but haven't yet had reason to use gfortran.

I've seen others with this problem on gcc-4.7 (http://ubuntuforums.org/showthread.php?t=2123821), so I wonder if this is from manually installing gcc-4.7. I followed the recipe from the accepted answer here here and here here.

Running lsb_release -a prints

Ubuntu 12.04.2 LTS

and running uname -r prints

3.2.0-39-generic-pae

Can anyone offer advice for why ld doesn't work?

You tried to make symbolic links against runtime libraries, not the ones that linker wants (*.a dev libs). Looks like the path issue. — Andrejs Cainikovs, Apr 01 '13 at 20:55

score 19 · Answer 1 · edited Feb 05 '22 at 17:36

19

What I did, I check on ubuntu if the versions of g++, gcc and gfortran are the same or not.

I guess it is better if you have all the three of same version.

# first check the versions:
gcc --version
g++ --version
gfortran --version
If versions are different, then install:
sudo apt-get update
apt-get install gcc-4.9 g++-4.9 gfortran-4.9

For me this resolved all the issues which I was facing while installing "TTR" package in R using RStudio on Ubuntu.

If you further run into the issue gfortran: command not found, make sure that you have /usr/bin/gfortran linking to the actual version of gfortran you have installed (e.g. linking to gfortran-4.9):

sudo update-alternatives --install /usr/bin/gfortran gfortran /usr/bin/gfortran-11 70

edited Feb 05 '22 at 17:36

slhck

940

answered Apr 04 '17 at 12:25

Manoj Kumar

291

2

This is the correct solution. None of the above solutions worked for me – Yonatan Simson Sep 02 '18 at 15:13
2

I am on gcc 6.5, but the same methods solved the issue. Interestingly, same source: an obscure R package. – Ufos Jan 28 '19 at 12:43
Yes, this was one best solution I could think of. – Manoj Kumar Feb 17 '19 at 14:13
4

More generally: apt install gfortran-<your GCC version>. – ZachB Jun 26 '20 at 18:15
1

On Ubuntu 22.04, my gcc and g++ were 11.3.0 but gfortran not found. I installed gfortran-11 since 11.3.0 and 11.3 did not exist – Kermit Jul 24 '23 at 12:45
In my case:
sudo update-alternatives --config g++, sudo update-alternatives --config gcc

and choose the same version as gfortran
– Le Quang Nam Feb 25 '24 at 05:51

score 9 · Answer 2 · edited Apr 20 '18 at 08:23

A little more explanation to Cloud Oliver's answer.

Find out the gcc version currently being used through this command.

$sudo update-alternatives --config gcc

* 2            /usr/bin/gcc-4.7   60        manual mode

The entry with * tells which version of GCC is being used. Just press enter to keep the current settings.

If it prints "no alternatives for gcc", you might have to use this command to find out the version:

apt-cache policy gcc

cd to the right gcc directory (replace the version number with yours):
```
cd /usr/lib/gcc/x86_64-linux-gnu/4.7/
```
You can search for libgfortran.a with the following command (optional). In my case it was present in the /usr/lib/gcc/x86_64-linux-gnu/4.8/ directory.
```
find /usr/lib/gcc/x86_64-linux-gnu/ -name libgfortran.a
```

Create the symlink:

sudo ln -s /usr/lib/gcc/x86_64-linux-gnu/4.8/libgfortran.a libgfortran.a

You should use the gfortran lib that matches the compiler instead of mixing versions. Manoj Kumar's answer below is correct. — ZachB, Jun 26 '20 at 18:13

score 7 · Accepted Answer · answered Apr 01 '13 at 20:02

7

You need to install gfortran. The error points out that the static lib for build-time linking is missing not the dynamic libs you tried to adjust.

answered Apr 01 '13 at 20:02

rfindeis

269

When I try sudo apt-get install gfortran, I get 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.... Any thoughts? – user Apr 01 '13 at 20:06
Well, on my system I get for dpkg -S /usr/lib/gcc/x86)64-linux-gnu/4.6/libgfortran.a the answer that this is from the gfortran-4.6 package. Gcc is looking for the .a file. If you installed another gcc version, the linker is looking inside a similarly named directory for libgfortran.a. – rfindeis Apr 01 '13 at 20:36
Looks like a valid answer. – Andrejs Cainikovs Apr 01 '13 at 20:59
Symbolic linking the 4.6 library for the 4.7 compiler might work. Also passing the correct path with -L (which is largely the same). If this fails you need to install the 4.7 version of gfortran from the ppa you used for gcc 4.7. What gfortran version do you have now? – rfindeis Apr 01 '13 at 21:00
I needed to use the same trick as installing gcc-4.7 to install gfortran-4.7. – user Apr 01 '13 at 23:43
I faced same error and eventually ~$ sudo apt-get install libgfortran-* to install all versions to cope with it. these sudo apt-get install r-cran-ks very useful which can let us install through terminal :) – Rγσ ξηg Lιαη Ημ 雷欧 May 20 '21 at 16:56

score 5 · Answer 4 · edited Nov 23 '14 at 12:27

5

Solution:

cd /usr/lib/gcc/x86_64-linux-gnu/4.6
sudo ln -s /usr/lib/gcc/x86_64-linux-gnu/4.8/libgfortran.a libgfortran.a

edited Nov 23 '14 at 12:27

Eric Carvalho

54,385

answered Nov 22 '14 at 04:18

Cloud Oliver

51

Could you make it a little more verbose? Maybe a separate cd line at least? – Volker Siegel Nov 22 '14 at 05:18
4

Please add an explanation. People should never blindly run commands they find on the internet. So please also don't write them. – s3lph Nov 23 '14 at 13:41
Thank you, this solved it for me! In my case it was cd /usr/lib/gcc/x86_64-linux-gnu/4.9.3 and then sudo ln -s /usr/lib/gcc/x86_64-linux-gnu/4.8/libgfortran.a libgfortran.a – Zhubarb Jan 29 '17 at 13:50

Cannot find -lgfortran

4 Answers4

If versions are different, then install:

Linked