구차니의 잡동사니 모음

odroid@odroid_2:/var/www/html/mediawiki/maintenance$ sudo php update.php

MediaWiki 1.27.4 Updater

Your composer.lock file is up to date with current dependencies!

Going to run database updates for minimonk-mw_

Depending on the size of your database this may take a while!

Abort with control-c in the next five seconds (skip this countdown with --quick) ... 0

Turning off Content Handler DB fields for this part of upgrade.

...have ipb_id field in ipblocks table.

...have ipb_expiry field in ipblocks table.

...already have interwiki table

...indexes seem up to 20031107 standards.

...have rc_type field in recentchanges table.

...index new_name_timestamp already set on recentchanges table.

...have user_real_name field in user table.

...querycache table already exists.

...objectcache table already exists.

...categorylinks table already exists.

...have pagelinks; skipping old links table updates

...il_from OK

...have rc_ip field in recentchanges table.

...index PRIMARY already set on image table.

...have rc_id field in recentchanges table.

...have rc_patrolled field in recentchanges table.

...logging table already exists.

...have user_token field in user table.

...have wl_notificationtimestamp field in watchlist table.

...watchlist talk page rows already present.

...user table does not contain user_emailauthenticationtimestamp field.

...page table already exists.

...have log_params field in logging table.

...logging table has correct log_title encoding.

...have ar_rev_id field in archive table.

...have page_len field in page table.

...revision table does not contain inverse_timestamp field.

...have rev_text_id field in revision table.

...have rev_deleted field in revision table.

...have img_width field in image table.

...have img_metadata field in image table.

...have user_email_token field in user table.

...have ar_text_id field in archive table.

...page_namespace is already a full int (int(11)).

...ar_namespace is already a full int (int(11)).

...rc_namespace is already a full int (int(11)).

...wl_namespace is already a full int (int(11)).

...qc_namespace is already a full int (int(11)).

...log_namespace is already a full int (int(11)).

...have img_media_type field in image table.

...already have pagelinks table.

...image table does not contain img_type field.

...already have unique user_name index.

...user_groups table exists and is in current format.

...have ss_total_pages field in site_stats table.

...user_newtalk table already exists.

...transcache table already exists.

...have iw_trans field in interwiki table.

...wl_notificationtimestamp is already nullable.

...index times already set on logging table.

...have ipb_range_start field in ipblocks table.

...no page_random rows needed to be set

...have user_registration field in user table.

...templatelinks table already exists

...externallinks table already exists.

...job table already exists.

...have ss_images field in site_stats table.

...langlinks table already exists.

...querycache_info table already exists.

...filearchive table already exists.

...have ipb_anon_only field in ipblocks table.

...index rc_ns_usertext already set on recentchanges table.

...index rc_user_text already set on recentchanges table.

...have user_newpass_time field in user table.

...redirect table already exists.

...querycachetwo table already exists.

...have ipb_enable_autoblock field in ipblocks table.

...index pl_namespace on table pagelinks includes field pl_from.

...index tl_namespace on table templatelinks includes field tl_from.

...index il_to on table imagelinks includes field il_from.

...have rc_old_len field in recentchanges table.

...have user_editcount field in user table.

...page_restrictions table already exists.

...have log_id field in logging table.

...have rev_parent_id field in revision table.

...have pr_id field in page_restrictions table.

...have rev_len field in revision table.

...have rc_deleted field in recentchanges table.

...have log_deleted field in logging table.

...have ar_deleted field in archive table.

...have ipb_deleted field in ipblocks table.

...have fa_deleted field in filearchive table.

...have ar_len field in archive table.

...have ipb_block_email field in ipblocks table.

...index cl_sortkey on table categorylinks includes field cl_from.

...have oi_metadata field in oldimage table.

...index usertext_timestamp already set on archive table.

...index img_usertext_timestamp already set on image table.

...index oi_usertext_timestamp already set on oldimage table.

...have ar_page_id field in archive table.

...have img_sha1 field in image table.

...protected_titles table already exists.

...have ipb_by_text field in ipblocks table.

...page_props table already exists.

...updatelog table already exists.

...category table already exists.

...category table already populated.

...have ar_parent_id field in archive table.

...have user_last_timestamp field in user_newtalk table.

...protected_titles table has correct pt_title encoding.

...have ss_active_users field in site_stats table.

...ss_active_users user count set...

...have ipb_allow_usertalk field in ipblocks table.

...pl_namespace, tl_namespace, il_to indices are already UNIQUE.

...change_tag table already exists.

...tag_summary table already exists.

...valid_tag table already exists.

...user_properties table already exists.

...log_search table already exists.

...have log_user_text field in logging table.

...l10n_cache table already exists.

...index ls_field_val already set on log_search table.

...index change_tag_rc_tag already set on change_tag table.

...have rd_interwiki field in redirect table.

...transcache tc_time already converted.

...*_mime_minor fields are already long enough.

...iwlinks table already exists.

...index iwl_prefix_title_from already set on iwlinks table.

...have ul_value field in updatelog table.

...have iw_api field in interwiki table.

...iwl_prefix key doesn't exist.

...have cl_collation field in categorylinks table.

...categorylinks up-to-date.

...module_deps table already exists.

...ar_page_revid key doesn't exist.

...index ar_revid already set on archive table.

...ll_lang is up-to-date.

...user_last_timestamp is already nullable.

...index user_email already set on user table.

...up_property in table user_properties already modified by patch patch-up_property.sql.

...uploadstash table already exists.

...user_former_groups table already exists.

...index type_action already set on logging table.

...have rev_sha1 field in revision table.

...batch conversion of user_options: nothing to migrate. done.

...user table does not contain user_options field.

...have ar_sha1 field in archive table.

...index page_redirect_namespace_len already set on page table.

...have us_chunk_inx field in uploadstash table.

...have job_timestamp field in job table.

Adding index page_user_timestamp to table revision ...done.

Adding ipb_parent_block_id field to table ipblocks ...done.

Adding index ipb_parent_block_id to table ipblocks ...done.

Table category contains cat_hidden field. Dropping ...done.

Adding rev_content_format field to table revision ...done.

Adding rev_content_model field to table revision ...done.

Adding ar_content_format field to table archive ...done.

Adding ar_content_model field to table archive ...done.

Adding page_content_model field to table page ...done.

Content Handler DB fields should be usable now.

Table site_stats contains ss_admins field. Dropping ...done.

Table recentchanges contains rc_moved_to_title field. Dropping ...done.

Creating sites table ...done.

Adding fa_sha1 field to table filearchive ...done.

Adding job_token field to table job ...done.

Adding job_attempts field to table job ...done.

Adding us_props field to table uploadstash ...done.

Modifying ug_group field of table user_groups ...done.

Modifying ufg_group field of table user_former_groups ...done.

Adding index pp_propname_page to table page_props ...done.

Adding index img_media_mime to table image ...done.

Making iwl_prefix_title_from index non-UNIQUE ...done.

Adding index iwl_prefix_from_title to table iwlinks ...done.

Adding ar_id field to table archive ...done.

Adding el_id field to table externallinks ...done.

Adding rc_source field to table recentchanges ...done.

Adding index log_user_text_type_time to table logging ...done.

Adding index log_user_text_time to table logging ...done.

Adding page_links_updated field to table page ...done.

Adding user_password_expires field to table user ...done.

Adding pp_sortkey field to table page_props ...done.

Table recentchanges contains rc_cur_time field. Dropping ...done.

Adding index wl_user_notificationtimestamp to table watchlist ...done.

Adding page_lang field to table page ...done.

Adding pl_from_namespace field to table pagelinks ...done.

Adding tl_from_namespace field to table templatelinks ...done.

Adding il_from_namespace field to table imagelinks ...done.

Modifying img_major_mime field of table image ...done.

Modifying oi_major_mime field of table oldimage ...done.

Modifying fa_major_mime field of table filearchive ...done.

Making user_id unsigned int ...done.

Modifying rc_comment field of table recentchanges ...done.

Dropping table hitcounter ...done.

Table site_stats contains ss_total_views field. Dropping ...done.

Table page contains page_counter field. Dropping ...done.

Dropping table msg_resource_links ...done.

Dropping table msg_resource ...done.

Creating bot_passwords table ...done.

Adding wl_id field to table watchlist ...done.

Dropping cl_collation index from table categorylinks ...done.

Adding index cl_collation_ext to table categorylinks ...done.

...collations up-to-date.

...site_stats is populated...done.

Checking existence of old default messages...done.

Populating rev_len column

...doing rev_id from 13 to 212

...doing rev_id from 213 to 412

...doing rev_id from 413 to 612

...doing rev_id from 613 to 812

...doing rev_id from 813 to 1012

...doing rev_id from 1013 to 1212

...doing rev_id from 1213 to 1412

...doing rev_id from 1413 to 1612

...doing rev_id from 1613 to 1812

...doing rev_id from 1813 to 2012

...doing rev_id from 2013 to 2212

...doing rev_id from 2213 to 2412

Populating ar_len column

...archive table seems to be empty.

rev_len and ar_len population complete [0 revision rows, 0 archive rows].

Populating rev_sha1 column

...doing rev_id from 13 to 212

...doing rev_id from 213 to 412

...doing rev_id from 413 to 612

...doing rev_id from 613 to 812

...doing rev_id from 813 to 1012

...doing rev_id from 1013 to 1212

...doing rev_id from 1213 to 1412

...doing rev_id from 1413 to 1612

...doing rev_id from 1613 to 1812

...doing rev_id from 1813 to 2012

...doing rev_id from 2013 to 2212

...doing rev_id from 2213 to 2412

Populating ar_sha1 column

...archive table seems to be empty.

Populating ar_sha1 column legacy rows

rev_sha1 and ar_sha1 population complete [0 revision rows, 0 archive rows].

Populating img_sha1 field

Done 0 files in 0.0 seconds

Fixing protocol-relative entries in the externallinks table...

Done, 0 rows updated.

Populating fa_sha1 field from fa_storage_key

Done 0 files in 0.0 seconds

Updating *_from_namespace fields in links tables.

...doing page_id from 1 to 200

Purging caches...done.

Done in 5.2 s. 

internal linkage

internal linkage를 가지는 이름은 외부 translation unit으로 공개되지 않는다. internal linkage를 가지는 이름은 다음과 같다.

namespace scope에 선언된 static specifier가 붙은 이름

namespace scope에 선언된 anonymous union의 데이터 멤버

namespace scope에 선언된 const 혹은 constexpr이 붙고 volatile은 아닌 변수

unnamed namespace에 선언된 모든 이름

external linkage

 위에서 설명한 internal linkage와 다르게 external linkage를 가지는 이름은 다른 translation unit과 공유된다. 다시 말해서 어떤 이름이 external linkage를 가진다면 그 이름은 서로 다른 translation unit에서 사용되더라도 같은 내용을 가져야 한다.

namespace scoep에 선언 된 이름 중 internal linkage가 아닌 이름.

block scope에 선언된 함수

block scope에 선언된 변수 중에서 extern으로 선언된 변수 

Internal Linkage: An identifier implementing internal linkage is not accessible outside the translation unit it is declared in. Any identifier within the unit can access an identifier having internal linkage. It is implemented by the keyword static. An internally linked identifier is stored in initialized or uninitialized segment of RAM.  

External Linkage: An identifier implementing external linkage is visible to every translation unit. Externally linked identifiers are shared between translation units and are considered to be located at the outermost level of the program. In practice, this means that you must define an identifier in a place which is visible to all, such that it has only one visible definition. It is the default linkage for globally scoped variables and functions. Thus, all instances of a particular identifier with external linkage refer to the same identifier in the program. The keyword extern implements external linkage.

When we use the keyword extern, we tell the linker to look for the definition elsewhere. Thus, the declaration of an externally linked identifier does not take up any space. Extern identifiers are generally stored in initialized/uninitialized or text segment of RAM. If uninitialized, the value of the identifier is set to 0 by the kernel.

That looks perfectly fine under the C99 rules. Because stack.c is compiled with both an extern and inline declaration of the function, it will be defined with external linkage and can also be inlined within that file.

Other files will have only the declaration, and so will link to the version with external linkage.

Note that the function isn't allowed to define any modifiable objects with static storage duration, or reference any functions or global variables that aren't extern. 

If you specify both inline and extern in the function definition, then the definition is used only for inlining. In no case is the function compiled on its own, not even if you refer to its address explicitly. Such an address becomes an external reference, as if you had only declared the function, and had not defined it.

This combination of inline and extern has almost the effect of a macro. The way to use it is to put a function definition in a header file with these keywords, and put another copy of the definition (lacking inline and extern) in a library file. The definition in the header file causes most calls to the function to be inlined. If any uses of the function remain, they refer to the single copy in the library. 

C99 inline semantics are often misunderstood. The inline specifier serves two purposes:

First, as a compiler hint in case of static inline and extern inline declarations. Semantics remain unchanged if you remove the specifier.

Second, in case of raw inline (ie without static or extern) to provide an inline definition as an alternative to an external one, which has to be present in a different translation unit. Not providing the external one is undefined behaviour, which will normally manifest as linking failure.

translation unit은 C++ compilation의 기본 단위입니다. <소스 파일 하나 + 직접/간접적으로 include된 헤더파일의 내용물(전처리기 조건에 따라 몇몇은 무시)>로 구성되어 있습니다.

translation unit 한개는 object file, library나 실행가능한 프로그램으로 컴파일 될 수 있습니다. 

A translation unit is the basic unit of compilation in C++. It consists of the contents of a single source file, plus the contents of any header files directly or indirectly included by it, minus those lines that were ignored using conditional preprocessing statements.

A single translation unit can be compiled into an object file, library, or executable program.

The notion of a translation unit is most often mentioned in the contexts of the One Definition Rule, and templates.