Error: org.macports.build for port uhd returned: command execution failed

[mxl8214@…]

I have OS X Yosemite and I am trying to run "sudo port install uhd" but failed.

Error: org.macports.build for port uhd returned: command execution failed
Please see the log file for port uhd for details:
    /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_science_uhd/uhd/main.log
To report a bug, follow the instructions in the guide:
    http://guide.macports.org/#project.tickets
Error: Processing of port uhd failed

[mxl8214@…]

This is the error log file

[larryv (Lawrence Velázquez)]

:warn:main The Xcode Command Line Tools don't appear to be installed; most ports will likely fail to build.
:warn:main Install them by running `xcode-select --install'.

Do this.

% xcode-select --install
% sudo port clean uhd
% sudo port install uhd

[dominic27@…]

after Xcode-select --install allow to run then before you try another terminal code type

% sudo xcode-select --reset

then continue with the (in my case)

% sudo port install gqrx

this solved the error message that the command line tools where not installed at every other run