/proc/self/root/proc/thread-self/root/usr/share/doc/sqlite-libs
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<h1 align="center">SQLite Source Repository</h1> This repository contains the complete source code for the[SQLite database engine](https://sqlite.org/). Some test scriptsare also included. However, many other test scriptsand most of the documentation are managed separately. ## Version Control SQLite sources are managed using the[Fossil](https://www.fossil-scm.org/), a distributed version control systemthat was specifically designed and written to support SQLite development.The [Fossil repository](https://sqlite.org/src/timeline) contains the urtext. If you are reading this on GitHub or some other Git repository or service,then you are looking at a mirror. The names of check-ins andother artifacts in a Git mirror are different from the officialnames for those objects. The official names for check-ins arefound in a footer on the check-in comment for authorized mirrors.The official check-in name can also be seen in the `manifest.uuid` filein the root of the tree. Always use the official name, not theGit-name, when communicating about an SQLite check-in. If you pulled your SQLite source code from a secondary source and want toverify its integrity, there are hints on how to do that in the[Verifying Code Authenticity](#vauth) section below. ## Obtaining The Code If you do not want to use Fossil, you can download tarballs or ZIParchives or [SQLite archives](https://sqlite.org/cli.html#sqlar) as follows: * Latest trunk check-in as [Tarball](https://www.sqlite.org/src/tarball/sqlite.tar.gz), [ZIP-archive](https://www.sqlite.org/src/zip/sqlite.zip), or [SQLite-archive](https://www.sqlite.org/src/sqlar/sqlite.sqlar). * Latest release as [Tarball](https://www.sqlite.org/src/tarball/sqlite.tar.gz?r=release), [ZIP-archive](https://www.sqlite.org/src/zip/sqlite.zip?r=release), or [SQLite-archive](https://www.sqlite.org/src/sqlar/sqlite.sqlar?r=release). * For other check-ins, substitute an appropriate branch name or tag or hash prefix in place of "release" in the URLs of the previous bullet. Or browse the [timeline](https://www.sqlite.org/src/timeline) to locate the check-in desired, click on its information page link, then click on the "Tarball" or "ZIP Archive" links on the information page. If you do want to use Fossil to check out the source tree,first install Fossil version 2.0 or later.(Source tarballs and precompiled binaries available[here](https://www.fossil-scm.org/fossil/uv/download.html). Fossil isa stand-alone program. To install, simply download or build the singleexecutable file and put that file someplace on your $PATH.)Then run commands like this: mkdir -p ~/sqlite ~/Fossils cd ~/sqlite fossil clone https://www.sqlite.org/src ~/Fossils/sqlite.fossil fossil open ~/Fossils/sqlite.fossil After setting up a repository using the steps above, you can alwaysupdate to the latest version using: fossil update trunk ;# latest trunk check-in fossil update release ;# latest official release Or type "fossil ui" to get a web-based user interface. ## Compiling for Unix-like systems First create a directory in which to placethe build products. It is recommended, but not required, that thebuild directory be separate from the source directory. Cd into thebuild directory and then from the build directory run the configurescript found at the root of the source tree. Then run "make". For example: tar xzf sqlite.tar.gz ;# Unpack the source tree into "sqlite" mkdir bld ;# Build will occur in a sibling directory cd bld ;# Change to the build directory ../sqlite/configure ;# Run the configure script make ;# Run the makefile. make sqlite3.c ;# Build the "amalgamation" source file make test ;# Run some tests (requires Tcl) See the makefile for additional targets. The configure script uses autoconf 2.61 and libtool. If the configurescript does not work out for you, there is a generic makefile named"Makefile.linux-gcc" in the top directory of the source tree that youcan copy and edit to suit your needs. Comments on the generic makefileshow what changes are needed. ## Using MSVC for Windows systems On Windows, all applicable build products can be compiled with MSVC.First open the command prompt window associated with the desired compilerversion (e.g. "Developer Command Prompt for VS2013"). Next, use NMAKEwith the provided "Makefile.msc" to build one of the supported targets. For example, from the parent directory of the source subtree named "sqlite": mkdir bld cd bld nmake /f ..\sqlite\Makefile.msc TOP=..\sqlite nmake /f ..\sqlite\Makefile.msc sqlite3.c TOP=..\sqlite nmake /f ..\sqlite\Makefile.msc sqlite3.dll TOP=..\sqlite nmake /f ..\sqlite\Makefile.msc sqlite3.exe TOP=..\sqlite nmake /f ..\sqlite\Makefile.msc test TOP=..\sqlite There are several build options that can be set via the NMAKE commandline. For example, to build for WinRT, simply add "FOR_WINRT=1" argumentto the "sqlite3.dll" command line above. When debugging into the SQLitecode, adding the "DEBUG=1" argument to one of the above command lines isrecommended. SQLite does not require [Tcl](http://www.tcl.tk/) to run, but a Tcl installationis required by the makefiles (including those for MSVC). SQLite containsa lot of generated code and Tcl is used to do much of that code generation. ## Source Code Tour Most of the core source files are in the **src/** subdirectory. The**src/** folder also contains files used to build the "testfixture" testharness. The names of the source files used by "testfixture" all beginwith "test".The **src/** also contains the "shell.c" filewhich is the main program for the "sqlite3.exe"[command-line shell](https://sqlite.org/cli.html) andthe "tclsqlite.c" file which implements the[Tcl bindings](https://sqlite.org/tclsqlite.html) for SQLite.(Historical note: SQLite began as a Tclextension and only later escaped to the wild as an independent library.) Test scripts and programs are found in the **test/** subdirectory.Additional test code is found in other source repositories.See [How SQLite Is Tested](http://www.sqlite.org/testing.html) foradditional information. The **ext/** subdirectory contains code for extensions. TheFull-text search engine is in **ext/fts3**. The R-Tree engine is in**ext/rtree**. The **ext/misc** subdirectory contains a number ofsmaller, single-file extensions, such as a REGEXP operator. The **tool/** subdirectory contains various scripts and programs usedfor building generated source code files or for testing or for generatingaccessory programs such as "sqlite3_analyzer(.exe)". ### Generated Source Code Files Several of the C-language source files used by SQLite are generated fromother sources rather than being typed in manually by a programmer. Thissection will summarize those automatically-generated files. To create allof the automatically-generated files, simply run "make target_source".The "target_source" make target will create a subdirectory "tsrc/" andfill it with all the source files needed to build SQLite, bothmanually-edited files and automatically-generated files. The SQLite interface is defined by the **sqlite3.h** header file, which isgenerated from src/sqlite.h.in, ./manifest.uuid, and ./VERSION. The[Tcl script](http://www.tcl.tk) at tool/mksqlite3h.tcl does the conversion.The manifest.uuid file contains the SHA3 hash of the particular check-inand is used to generate the SQLITE\_SOURCE\_ID macro. The VERSION filecontains the current SQLite version number. The sqlite3.h header is reallyjust a copy of src/sqlite.h.in with the source-id and version number insertedat just the right spots. Note that comment text in the sqlite3.h file isused to generate much of the SQLite API documentation. The Tcl scriptsused to generate that documentation are in a separate source repository. The SQL language parser is **parse.c** which is generated from a grammar inthe src/parse.y file. The conversion of "parse.y" into "parse.c" is doneby the [lemon](./doc/lemon.html) LALR(1) parser generator. The source codefor lemon is at tool/lemon.c. Lemon uses the tool/lempar.c file as atemplate for generating its parser.Lemon also generates the **parse.h** header file, at the same time itgenerates parse.c. The **opcodes.h** header file contains macros that define the numberscorresponding to opcodes in the "VDBE" virtual machine. The opcodes.hfile is generated by scanning the src/vdbe.c source file. TheTcl script at ./mkopcodeh.tcl does this scan and generates opcodes.h.A second Tcl script, ./mkopcodec.tcl, then scans opcodes.h to generatethe **opcodes.c** source file, which contains a reverse mapping fromopcode-number to opcode-name that is used for EXPLAIN output. The **keywordhash.h** header file contains the definition of a hash tablethat maps SQL language keywords (ex: "CREATE", "SELECT", "INDEX", etc.) intothe numeric codes used by the parse.c parser. The keywordhash.h file isgenerated by a C-language program at tool mkkeywordhash.c. The **pragma.h** header file contains various definitions used to parseand implement the PRAGMA statements. The header is generated by ascript **tool/mkpragmatab.tcl**. If you want to add a new PRAGMA, editthe **tool/mkpragmatab.tcl** file to insert the information needed by theparser for your new PRAGMA, then run the script to regenerate the**pragma.h** header file. ### The Amalgamation All of the individual C source code and header files (both manually-editedand automatically-generated) can be combined into a single big source file**sqlite3.c** called "the amalgamation". The amalgamation is the recommendedway of using SQLite in a larger application. Combining all individualsource code files into a single big source code file allows the C compilerto perform more cross-procedure analysis and generate better code. SQLiteruns about 5% faster when compiled from the amalgamation versus when compiledfrom individual source files. The amalgamation is generated from the tool/mksqlite3c.tcl Tcl script.First, all of the individual source files must be gathered into the tsrc/subdirectory (using the equivalent of "make target_source") then thetool/mksqlite3c.tcl script is run to copy them all together in just theright order while resolving internal "#include" references. The amalgamation source file is more than 200K lines long. Some symbolicdebuggers (most notably MSVC) are unable to deal with files longer than 64Klines. To work around this, a separate Tcl script, tool/split-sqlite3c.tcl,can be run on the amalgamation to break it up into a single small C filecalled **sqlite3-all.c** that does #include on about seven other filesnamed **sqlite3-1.c**, **sqlite3-2.c**, ..., **sqlite3-7.c**. In this way,all of the source code is contained within a single translation unit sothat the compiler can do extra cross-procedure optimization, but noindividual source file exceeds 32K lines in length. ## How It All Fits Together SQLite is modular in design.See the [architectural description](http://www.sqlite.org/arch.html)for details. Other documents that are useful in(helping to understand how SQLite works include the[file format](http://www.sqlite.org/fileformat2.html) description,the [virtual machine](http://www.sqlite.org/opcode.html) that runsprepared statements, the description of[how transactions work](http://www.sqlite.org/atomiccommit.html), andthe [overview of the query planner](http://www.sqlite.org/optoverview.html). Years of effort have gone into optimizing SQLite, bothfor small size and high performance. And optimizations tend to result incomplex code. So there is a lot of complexity in the current SQLiteimplementation. It will not be the easiest library in the world to hack. Key files: * **sqlite.h.in** - This file defines the public interface to the SQLite library. Readers will need to be familiar with this interface before trying to understand how the library works internally. * **sqliteInt.h** - this header file defines many of the data objects used internally by SQLite. In addition to "sqliteInt.h", some subsystems have their own header files. * **parse.y** - This file describes the LALR(1) grammar that SQLite uses to parse SQL statements, and the actions that are taken at each step in the parsing process. * **vdbe.c** - This file implements the virtual machine that runs prepared statements. There are various helper files whose names begin with "vdbe". The VDBE has access to the vdbeInt.h header file which defines internal data objects. The rest of SQLite interacts with the VDBE through an interface defined by vdbe.h. * **where.c** - This file (together with its helper files named by "where*.c") analyzes the WHERE clause and generates virtual machine code to run queries efficiently. This file is sometimes called the "query optimizer". It has its own private header file, whereInt.h, that defines data objects used internally. * **btree.c** - This file contains the implementation of the B-Tree storage engine used by SQLite. The interface to the rest of the system is defined by "btree.h". The "btreeInt.h" header defines objects used internally by btree.c and not published to the rest of the system. * **pager.c** - This file contains the "pager" implementation, the module that implements transactions. The "pager.h" header file defines the interface between pager.c and the rest of the system. * **os_unix.c** and **os_win.c** - These two files implement the interface between SQLite and the underlying operating system using the run-time pluggable VFS interface. * **shell.c.in** - This file is not part of the core SQLite library. This is the file that, when linked against sqlite3.a, generates the "sqlite3.exe" command-line shell. The "shell.c.in" file is transformed into "shell.c" as part of the build process. * **tclsqlite.c** - This file implements the Tcl bindings for SQLite. It is not part of the core SQLite library. But as most of the tests in this repository are written in Tcl, the Tcl language bindings are important. * **test*.c** - Files in the src/ folder that begin with "test" go into building the "testfixture.exe" program. The testfixture.exe program is an enhanced Tcl shell. The testfixture.exe program runs scripts in the test/ folder to validate the core SQLite code. The testfixture program (and some other test programs too) is built and run when you type "make test". * **ext/misc/json1.c** - This file implements the various JSON functions that are built into SQLite. There are many other source files. Each has a succinct header comment thatdescribes its purpose and role within the larger system. <a name="vauth"></a>## Verifying Code Authenticity The `manifest` file at the root directory of the source treecontains either a SHA3-256 hash (for newer files) or a SHA1 hash (forolder files) for every source file in the repository.The name of the version of the entire source tree is just theSHA3-256 hash of the `manifest` file itself, possibly with thelast line of that file omitted if the last line begins with"`# Remove this line`".The `manifest.uuid` file should contain the SHA3-256 hash of the`manifest` file. If all of the above hash comparisons are correct, thenyou can be confident that your source tree is authentic and unadulterated. The format of the `manifest` file should be mostly self-explanatory, butif you want details, they are available[here](https://fossil-scm.org/fossil/doc/trunk/www/fileformat.wiki#manifest). ## Contacts The main SQLite website is [http://www.sqlite.org/](http://www.sqlite.org/)with geographically distributed backups at[http://www2.sqlite.org/](http://www2.sqlite.org) and[http://www3.sqlite.org/](http://www3.sqlite.org).