# SWI-Prolog has check\_installation/0 **URL:** \ **Category:** Nice to know\ **Created:** [July 29, 2020, 1:08pm UTC](https://swi-prolog.discourse.group/t/swi-prolog-has-check-installation-0/2716 "2020-07-29T13:08:56Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![EricGT](https://avatars.discourse-cdn.com/v4/letter/e/f1d935/32.png) [@EricGT](https://swi-prolog.discourse.group/u/EricGT)\ **Post date:** [July 29, 2020, 1:08pm UTC](https://swi-prolog.discourse.group/t/swi-prolog-has-check-installation-0/2716/1 "2020-07-29T13:08:56Z")
If you get errors like ```prolog ERROR: source_sink `library(http/http_unix_daemon)' does not exist ``` then [check\_installation/0](https://www.swi-prolog.org/pldoc/doc/_SWI_/library/check_installation.pl) might help. > **Windows Example (Click here to expand)** > > ```nohighlight > ?- check_installation. > % Checking your SWI-Prolog kit for common issues ... > % > % Version: ............. 8.3.4-18-ge5d07a583 > % Address bits: ........ 64 > % Architecture: ........ x64-win64 > % Installed at: ........ c:/program files/swipl > % Cores: ............... 4 > % > % Checking tcmalloc ............................ not present > Warning: See http://www.swi-prolog.org/build/issues/tcmalloc.html > % Checking gmp ................................. ok > % Loading library(archive) ..................... ok > % Supported filters: bzip2, compress, gzip, grzip, lrzip, lzip, lzma, lzop, none, rpm, uu, xz > % Supported formats: 7zip, ar, cab, cpio, empty, gnutar, iso9660, lha, mtree, rar, raw, tar, xar, zip > % Loading library(cgi) ......................... ok > % Loading library(crypt) ....................... ok > % Loading library(bdb) ......................... ok > % Loading library(double_metaphone) ............ ok > % Loading library(filesex) ..................... ok > % Loading library(http/http_stream) ............ ok > % Loading library(http/json) ................... ok > % Loading library(http/jquery) ................. ok > % jQuery from c:/program files/swipl/library/http/web/js/jquery-1.11.3.min.js > % Loading library(isub) ........................ ok > % Loading library(jpl) ... > % Extended DLL search path with > % 'c:/Program Files/Java/jdk-12/bin/server' > % 'c:/Program Files/Java/jdk-12/bin' > ................................................ ok > % Loading library(memfile) ..................... ok > % Loading library(odbc) ........................ ok > % Loading library(pce) ......................... ok > % Loading library(pcre) ........................ ok > % Loading library(pdt_console) ................. ok > % Loading library(porter_stem) ................. ok > % Loading library(process) ..................... ok > % Loading library(protobufs) ................... ok > % Loading library(readutil) .................... ok > % Loading library(semweb/rdf_db) ............... ok > % Loading library(semweb/rdf_ntriples) ......... ok > % Loading library(semweb/turtle) ............... ok > % Loading library(sgml) ........................ ok > % Loading library(sha) ......................... ok > % Loading library(snowball) .................... ok > % Loading library(socket) ...................... ok > % Loading library(ssl) ......................... ok > % Loading library(crypto) ...................... ok > % Loading library(table) ....................... ok > % Loading library(time) ........................ ok > % Loading library(unicode) ..................... ok > % Loading library(uri) ......................... ok > % Loading library(uuid) ........................ ok > % Loading library(zlib) ........................ ok > % Loading library(yaml) ........................ ok > Warning: Found 1 issues. > true. > > ``` > **Ubuntu Example (Click here to expand)** > > ```nohighlight > ?- check_installation. > % Checking your SWI-Prolog kit for common issues ... > % > % Version: ............. 8.3.4 > % Address bits: ........ 64 > % Architecture: ........ x86_64-linux > % Installed at: ........ /usr/lib/swi-prolog > % Cores: ............... 4 > % > % Checking tcmalloc ............................ not present > Warning: See http://www.swi-prolog.org/build/issues/tcmalloc.html > % Checking gmp ................................. ok > % Loading library(archive) ..................... ok > % Supported filters: bzip2, compress, gzip, grzip, lrzip, lzip, lzma, lzop, none, rpm, uu, xz > % Supported formats: 7zip, ar, cab, cpio, empty, gnutar, iso9660, lha, mtree, rar, raw, tar, xar, zip > % Loading library(cgi) ......................... ok > % Loading library(crypt) ....................... ok > Warning: library(bdb) .......................... NOT FOUND > Warning: See http://www.swi-prolog.org/build/issues/bdb.html > % Loading library(double_metaphone) ............ ok > % Loading library(filesex) ..................... ok > % Loading library(http/http_stream) ............ ok > % Loading library(http/json) ................... ok > % Loading library(http/jquery) ................. ok > % jQuery from /usr/share/javascript/jquery/jquery.min.js > % Loading library(isub) ........................ ok > % Loading library(jpl) ......................... FAILED > Warning: Cannot load required shared library > Warning: See http://www.swi-prolog.org/build/issues/jpl.html > % Loading library(memfile) ..................... ok > % Loading library(odbc) ........................ ok > % Loading library(pce) ......................... ok > % Loading library(pcre) ........................ ok > % Loading library(pdt_console) ................. ok > % Loading library(porter_stem) ................. ok > % Loading library(process) ..................... ok > % Loading library(protobufs) ................... ok > % Loading library(editline) .................... ok > % Loading library(readline) .................... ok > % Loading library(readutil) .................... ok > % Loading library(rlimit) ...................... ok > % Loading library(semweb/rdf_db) ............... ok > % Loading library(semweb/rdf_ntriples) ......... ok > % Loading library(semweb/turtle) ............... ok > % Loading library(sgml) ........................ ok > % Loading library(sha) ......................... ok > % Loading library(snowball) .................... ok > % Loading library(socket) ...................... ok > % Loading library(ssl) ......................... ok > % Loading library(crypto) ...................... ok > % Loading library(syslog) ...................... ok > % Loading library(table) ....................... ok > % Loading library(time) ........................ ok > % Loading library(tipc/tipc) ................... ok > % Loading library(unicode) ..................... ok > % Loading library(uri) ......................... ok > % Loading library(uuid) ........................ ok > % Loading library(zlib) ........................ ok > % Loading library(yaml) ........................ ok > Warning: Found 3 issues. > true. > > ``` * * * Side note: The reason for the error is that I pulled the code ([plweb](http://eu.swi-prolog.org/pldoc/doc/scratch/swipl/src/plweb/index.html)) down using git on Ubuntu on WSL 2 but started SWI-Prolog from Windows, i.e. `swipl -l load.pl`. ---
**Author:** ![jan](https://yyz2.discourse-cdn.com/free1/user_avatar/swi-prolog.discourse.group/jan/32/4_2.png) [@jan](https://swi-prolog.discourse.group/u/jan)\ **Post date:** [July 29, 2020, 1:24pm UTC](https://swi-prolog.discourse.group/t/swi-prolog-has-check-installation-0/2716/2 "2020-07-29T13:24:23Z")
The problem probably remains that plweb uses the `library(http/http_unix_daemon)` ☹ Code may require some changes to run on Windows (it should run on the WSL version).