<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Dear all,<div class="">I receive an error message when trying to install ipopt on Linux. I have</div><div class=""><ul class="MailOutline"><li class="">downloaded ipopt 3.12.8 from <a href="https://www.coin-or.org/download/source/Ipopt/Ipopt-3.12.8.tgz" class="">here</a> </li><li class="">unzipped the archive in /Ipopt-3.12.8/</li><li class="">installed BLAS, Lapack and ASL as recommended in the ipopt documentation</li><li class="">$mkdir /Ipopt-3.12.8/build</li><li class="">$cd Ipopt-3.12.8/build</li><li class="">$../configure --prefix=/home/ipopt_directory</li></ul><div class=""><br class=""></div></div><div class="">and when I run $make, I get the following error</div><div class=""><br class=""></div><div class=""><div class=""><font face="Courier" style="font-size: 14px;" class="">g++ -O3 -pipe -DNDEBUG -Wparentheses -Wreturn-type -Wcast-qual -Wall -Wpointer-arith -Wwrite-strings -Wconversion -Wno-unknown-pragmas -Wno-long-long -DIPOPT_BUILD -o .libs/ipopt ampl_ipopt.o ./.libs/libipoptamplinterface.so /obs/username/Ipopt-3.12.8/build/Ipopt/src/Interfaces/.libs/libipopt.so ../../Interfaces/.libs/libipopt.so /obs/user_name/Ipopt-3.12.8/build/ThirdParty/ASL/.libs/libcoinasl.so /obs/user_name/Ipopt-3.12.8/build/ThirdParty/Lapack/.libs/libcoinlapack.so -L/usr/lib/gcc/x86_64-redhat-linux/4.4.6 -L/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../lib64 -L/lib/../lib64 -L/usr/lib/../lib64 -L/opt/intel/clck/2018.1/lib/intel64 -L/opt/intel/compilers_and_libraries_2018.1.163/linux/ipp/lib/intel64 -L/opt/intel/compilers_and_libraries_2018.1.163/linux/compiler/lib/intel64_lin -L/opt/intel/compilers_and_libraries_2018.1.163/linux/mkl/lib/intel64_lin -L/opt/intel/compilers_and_libraries_2018.1.163/linux/tbb/lib/intel64/gcc4.4 -L/opt/intel/compilers_and_libraries_2018.1.163/linux/daal/lib/intel64_lin -L/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../.. /obs/user_name/Ipopt-3.12.8/build/ThirdParty/Blas/.libs/libcoinblas.so -lgfortranbegin -lgfortran -lm -ldl -Wl,--rpath -Wl,/obs/user_name/ipopt//lib</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">/obs/user_name/Ipopt-3.12.8/build/ThirdParty/ASL/.libs/libcoinasl.so: undefined reference to `clock_gettime'</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">collect2: ld returned 1 exit status</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[3]: *** [ipopt] Error 1</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[3]: Leaving directory `/cluster3_home/user_name/Ipopt-3.12.8/build/Ipopt/src/Apps/AmplSolver'</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[2]: *** [all-recursive] Error 1</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[2]: Leaving directory `/cluster3_home/user_name/Ipopt-3.12.8/build/Ipopt/src/Apps'</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[1]: *** [all-recursive] Error 1</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make[1]: Leaving directory `/cluster3_home/user_name/Ipopt-3.12.8/build/Ipopt'</font></div><div class=""><font face="Courier" style="font-size: 14px;" class="">make: *** [all-recursive] Error 1</font></div></div><div class=""><br class=""></div><div class="">I am aware that one possible <a href="https://stackoverflow.com/questions/2418157/ubuntu-linux-c-error-undefined-reference-to-clock-gettime-and-clock-settim" class="">solution</a> is to add the -lrt flag, but I am not sure where nor how to insert it (in the makefile?). Do you know a way around this problem? </div><div class=""><br class=""></div><div class="">Thank you for your help</div><div class="">Best,</div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>