SQLite源码剖析(6)

/*

** Add the ability to override 'extern'

*/

//定义extern的宏，可使用SQLITE_EXTERN来完成extern功能

#ifndef SQLITE_EXTERN

# define SQLITE_EXTERN extern

#endif

//定义SQLITE_API宏

#ifndef SQLITE_API

# define SQLITE_API

#endif

 

 

/* no-op宏经常在接口前标记那些实验性的和不推荐的接口。新应用程序最好

**不使用不推荐的接口，它们支持向后兼容。程序员必须意识到实验性接口

**会在某个版本中改变

** These no-op macros are used in front of interfaces to mark those

** interfaces as either deprecated or experimental.  New applications

** should not use deprecated interfaces - they are support for backwards

** compatibility only.  Application writers should be aware that

** experimental interfaces are subject to change in point releases.

**这些宏在他们需要时，能实现编译器魔法compiler magic警告信息，

**编译器魔法最终产生BUG报告，编译器会试着使用noop宏。

** These macros used to resolve to various kinds of compiler magic that

** would generate warning messages when they were used.  But that

** compiler magic ended up generating such a flurry of bug reports

** that we have taken it all out and gone back to using simple

** noop macros.

*/

#define SQLITE_DEPRECATED

#define SQLITE_EXPERIMENTAL

 

/*

** Ensure these symbols were not defined by some previous header file.

*/

//如果SQLITE_VERSION、SQLITE_VERSION_NUMBER标志已经定义，则取消

#ifdef SQLITE_VERSION

# undef SQLITE_VERSION

#endif

#ifdef SQLITE_VERSION_NUMBER

# undef SQLITE_VERSION_NUMBER

#endif

 

/*

** CAPI3REF: Compile-Time Library Version Numbers

** SQLITE_VERSION 宏为版本号，[X.Y.Z的SQLITE版本号中,X是主版本号，Y

**是次版本号，Z是发行号

** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header

** evaluates to a string literal that is the SQLite version in the

** format "X.Y.Z" where X is the major version number (always 3 for

** SQLite3) and Y is the minor version number and Z is the release number.)^

** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves

** to an integer with the value (X*1000000 + Y*1000 + Z) where X, Y,

**and Z are the same numbers used in [SQLITE_VERSION].)^

** SQLITE_VERSION_NUMBER根据SQLITE_VERSION中版本号计算一个

**整数（X*1000000 + Y*1000 + Z）

** The SQLITE_VERSION_NUMBER for any given release of SQLite will also

** be larger than the release from which it is derived.  Either Y will

** be held constant and Z will be incremented or else Y will be incremented

** and Z will be reset to zero.

**

** Since version 3.6.18, SQLite source code has been stored in the

** <a href="http://www.fossil-scm.org/">Fossil configuration management

** system</a>.  ^The SQLITE_SOURCE_ID macro evalutes to

** a string which identifies a particular check-in of SQLite

** within its configuration management system.  ^The SQLITE_SOURCE_ID

** string contains the date and time of the check-in (UTC) and an SHA1

** hash of the entire source tree.

** SQLITE_SOURCE_ID 为一个字符串，为SQLITE配置管理系统中的check-in

**详情包含check-in的日期和时间以及整个源码树的SHA1哈希

** See also: [sqlite3_libversion()],

** [sqlite3_libversion_number()], [sqlite3_sourceid()],

** [sqlite_version()] and [sqlite_source_id()].

*/

//定义版本号，并计算SQLITE_VERSION_NUMBER

#define SQLITE_VERSION        "3.6.23.1"

#define SQLITE_VERSION_NUMBER 3006023

#define SQLITE_SOURCE_ID      "2010-03-26 22:28:06 b078b588d617e07886ad156e9f54ade6d823568e"

 

/*

** CAPI3REF: Run-Time Library Version Numbers

** KEYWORDS: sqlite3_version, sqlite3_sourceid

** 这些接口通过库而不是头文件提供了

*SQLITE_VERSION、SQLITE_VERSION_NUMBER以**及SQLITE_SOURCE_ID宏

**的相同信息

** These interfaces provide the same information as the [SQLITE_VERSION],

** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** but are associated with the library instead of the header file.  ^(Cautious

** programmers might include assert() statements in their application to

** verify that values returned by these interfaces match the macros in

** the header, and thus insure that the application is

** compiled with matching library and header files.

**可小心地通过包含以下的assert()声明，在应用程序核实匹配头文件中宏的

**这些接口，以确保应用程序使用相匹配的库和头文件编译

** <blockquote><pre>

** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );

** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );

** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );

** </pre></blockquote>)^

声明：本SQLite源码剖析系列为刘兴(http://deepfuture.iteye.com/)原创，未经笔者授权，任何人和机构不能转载