Hi all
I have installed lapack library in my linux system using both pacman package manager and conda, but when i wanted to use its subroutines in my fortran programs i got error below:
$ gfortran test.f90
/home/linuxbrew/.linuxbrew/bin/ld: /tmp/ccmmwhkj.o: in function
MAIN__': test.f90:(.text+0xdb): undefined reference tosgesv_’
collect2: error: ld returned 1 exit status
Hi @ELNS, you have to link against lapack such as
gfortran test.f90 -llapack
In the future, our Fortran Package Manger (fpm) will be able to do this for you, but for now you have to do it manually one way or another.
I have another question:
Should i mention all used libraries in your suggested command?
For example : $ gfortran test.f90 -l lapack blas
That depends on your Lapack installation. The syntax is -llapack -lblas.
Thank you very mush 
I am so glad that i am here.
We are happy to have you here!