Error while installing json gem mkmf rb can t find header files for ruby

Question

For context  it on a remote server which has a firewall  I m setting up my environment through a proxy  I have ruby 1 8 7  When I try to gem install    sudo gem install --http-proxy  lt host address gt   lt port gt  json   I get the following error   Building native extensions   This could take a while    ERROR   Error installing json          ERROR  Failed to build gem native extension    usr bin ruby extconf rb mkmf rb can t find header files for ruby at  usr lib ruby ruby h  Gem files will remain installed in  usr lib64 ruby gems 1 8 gems json-1 8 1 for inspection  Results logged to  usr lib64 ruby gems 1 8 gems json-1 8 1 ext json ext generator gem make out   Since I was unsure what the problem is  I googled and found these   gem install  Failed to build gem native extension  can  39 t find header files   - the instructions here seem to be specific to the gem being installed  How to install json gem - Failed to build gem native extension   This seems to be slightly different error    Any hints  Thanks

User · Answer

Xcode 11   macOS Catalina  On Xcode 11   macOS Catalina  the header files are no longer in the old location and the old  Library Developer CommandLineTools Packages macOS SDK headers for macOS 10 14 pkg file is no longer available   Instead  the headers are now installed to the  usr include directory of the current SDK path    Applications Xcode app Contents Developer Platforms MacOSX platform Developer SDKs MacOSX sdk usr include   Most of this directory can be found by using the output of xcrun --show-sdk-path  And if you add this path to the CPATH environment variable  then build scripts  including those called via bundle  will generally be able to find it   I resolved this by setting my CPATH in my  zshrc file   export CPATH    xcrun --show-sdk-path  usr include    After opening a new shell  or running source  zshrc   I no longer receive the error message mkmf rb can t find header files for ruby at  usr lib ruby ruby h and the rubygems install properly      Note on Building to Non-macOS Platforms      If you are building to non-macOS platforms  such as iOS tvOS watchOS  this change will attempt to include the macOS SDK in those platforms  causing build errors  To resolve  either don t set CPATH environment variable on login  or temporarily set it to blank when running xcodebuild like so   CPATH    xcodebuild --some-args

User · Answer

On Mac 10 14  the header files don t seem to be installed in the correct place  Rather than changing paths like the other fixes  I was able to just run this   open  Library Developer CommandLineTools Packages macOS SDK headers for macOS 10 14 pkg   Follow the instructions and it resolved this problem for me

User · Answer

For Ubuntu 18  after checking log file mentioned while install  Results logged to  var canvas vendor bundle ruby 2 5 0 extensions x86 64-linux 2 5 0 nio4r-2 5 2 gem make out  with  less  var canvas vendor bundle ruby 2 5 0 extensions x86 64-linux 2 5 0 nio4r-2 5 2 gem make out   I noticed that make is not found  So installed make by  sudo apt-get install make   everything worked

User · Answer

in case you use SUSE  sudo yast2 -i ruby-devel

User · Answer

sudo apt-get --reinstall install ruby   try it for ubuntu 16 04

User · Answer

Most voted solution didn t work on my machine  linux mint 18 04   After a careful look  i found that g   was missing  Solved with      sudo apt-get install g

User · Answer

Xcode -  Preferences -  Locations  change Command Line Tools to Xcode 11 2 1

User · Answer

For Xcode 11 on macOS 10 14  this can happen even after installing Xcode and installing command-line tools and accepting the license with    sudo xcode-select --install sudo xcodebuild -license accept   The issue is that Xcode 11 ships the macOS 10 15 SDK which includes headers for ruby2 6  but not for macOS 10 14 s ruby2 3  You can verify that this is your problem by running  ruby -rrbconfig -e  puts RbConfig  CONFIG  rubyhdrdir      which on macOS 10 14 with Xcode 11 prints the non-existent path   Applications Xcode app Contents Developer Platforms MacOSX platform Developer SDKs MacOSX10 15 sdk System Library Frameworks Ruby framework Versions 2 3 usr include ruby-2 3 0   However  Xcode 11 installs a macOS 10 14 SDK within  Library Developer CommandLineTools SDKs MacOS10 14 sdk  It isn t necessary to pollute the system directories by installing the old header files as suggested in other answers  Instead  by selecting that SDK  the appropriate ruby2 3 headers will be found   sudo xcode-select --switch  Library Developer CommandLineTools ruby -rrbconfig -e  puts RbConfig  CONFIG  rubyhdrdir      This should now correctly print   Library Developer CommandLineTools SDKs MacOSX10 14 sdk System Library Frameworks Ruby framework Versions 2 3 usr include ruby-2 3 0   Likewise  gem install should work while that SDK is selected   To switch back to the current Xcode SDK  use  sudo xcode-select --switch  Applications Xcode app

User · Answer

In case that you are using ruby 2 0 or 2 2  thanks  patrick-davey  or 2 3  thanks  juanitofatas    sudo apt-get install ruby-dev sudo apt-get install ruby2 0-dev sudo apt-get install ruby2 2-dev sudo apt-get install ruby2 3-dev   And you get the pattern here

User · Answer

You may need to install gcc after install ruby-devel

User · Answer

I had a similar problem using cygwin to run the following command     gem install rerun   I solved it by installing the following cygwin packages    ruby-devel libffi-devel gcc-core gcc-g   make automake1 15

User · Answer

I also encountered this problem because I install Ruby on Ubuntu via brightbox  and I thought ruby-dev is the trunk of ruby  So I did not install  Install ruby2 3-dev fixes it   sudo apt-get install ruby2 3-dev

User · Answer

You need to install the entire ruby and not just the minimum package  The correct command to use is   sudo apt install ruby-full   The following command will also not install a complete ruby   sudo apt-get install ruby2 3-dev

User · Answer

For those who are getting this on Mac OS X you may need to run the following command to install the XCode command-line tools  even if you already have XCode installed   sudo xcode-select --install   Also you must agree the terms and conditions of XCode by running the following command   sudo xcodebuild -license

User · Answer

BEFORE you follow the tip from Joki s answer  below  and IF    you have MacOS 10 14 6  at  Library Developer CommandLineTools SDKs  you have folders MacOSX sdk symbolic   MacOSX10 14 sdk  MacOSX10 15 sdk  Move MacOSX10 15 sdk to anywhere  admin privileges needs   Delete symbolic link  admin privileges needs   At  Library Developer CommandLineTools SDKs  create another symbolic link now to MacOSX10 14 sdk folder using  admin privileges needs  sudo ln -s  Library Developer CommandLineTools SDKs MacOSX10 14 sdk MacOSX sdk  Now you can follow Joki s answer   WARNING  If you move MacOSX10 15 sdk folder to  Library Developer CommandLineTools SDKs  again  the command ruby -rrbconfig -e  puts RbConfig  CONFIG  quot rubyhdrdir quot     will show  MacOSX10 15 sdk folder like default again  nowadays I dunno how to fix it  My suggestion  compress the folder and put the original folder until fix will be available

User · Answer

In Fedora 21 and up  you simply open a terminal and install the Ruby Development files as root   dnf install ruby-devel

User · Answer

Modern era update  as stated by mimoralea      In case that you are using ruby 2 0 or 2 2  thanks  patrick-davey    sudo apt-get install ruby2 0-dev sudo apt-get install ruby2 2-dev sudo apt-get install ruby2 3-dev    or  generic way    sudo apt-get install ruby-dev       or  sudo apt-get install ruby ruby -e  puts RUBY VERSION   d    d     -dev      The first link you   ve posted is exactly your case  there is no ruby development environment installed  Development env is needed to compile ruby extensions  which are mostly written in C  Proxy has nothing to do with the problem  everything is downloaded fine  just compilation fails   I would suggest you to install ruby-dev  ruby-devel for rpm-based distros  package onto you target machine   gcc package might be needed as well   Try     sudo apt-get install ruby-dev   Or  for Redhat distro     sudo yum install ruby-devel   Or  for  open SuSE     sudo zypper install ruby-devel

User · Answer

I faced a similar issue on Xcode 12 with macOS 10 15 and cocoapods  Just make sure that the xcode-select command points to the SDK you want to build against  It should build without issues afterwards

[json] Error while installing json gem 'mkmf.rb can't find header files for ruby'

Xcode 11 / macOS Catalina

Note on Building to Non-macOS Platforms

Examples related to json

Examples related to ruby

Examples related to rubygems