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Comment:Remove a lot of the text describing extended format options from the documentation on sqlite3_mprintf() and friends, since that information is now covered by the separate printf.html document. Provide links to that other document. No changes to code.
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SHA3-256: 99eec556f065ad19548e48d1f4ae0a3767b4e82e1c83fa2365062e3c5e0071fb
User & Date: drh 2018-02-20 13:46:20.902
Context
2018-02-20
15:23
Optimize calls to sqlite3_mprintf("%z...") so that they attempt to append text onto the end of the existing memory allocation rather than reallocating and copying. (check-in: 4bc8a48e64 user: drh tags: trunk)
13:46
Remove a lot of the text describing extended format options from the documentation on sqlite3_mprintf() and friends, since that information is now covered by the separate printf.html document. Provide links to that other document. No changes to code. (check-in: 99eec556f0 user: drh tags: trunk)
2018-02-19
22:46
Enhance the string formatter (used by printf()) so that the width and precision of string substitution operators refer to characters instead of bytes when the alternate-form-2 flag ("!") is used. Also fix the %c substition to always work within unicode, regardless of the alternate-form-2 flag. (check-in: c883c4d33f user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/sqlite.h.in.
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void sqlite3_free_table(char **result);

/*
** CAPI3REF: Formatted String Printing Functions
**
** These routines are work-alikes of the "printf()" family of functions
** from the standard C library.
** These routines understand most of the common K&R formatting options,

** plus some additional non-standard formats, detailed below.
** Note that some of the more obscure formatting options from recent
** C-library standards are omitted from this implementation.
**
** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
** results into memory obtained from [sqlite3_malloc()].
** The strings returned by these two routines should be
** released by [sqlite3_free()].  ^Both routines return a
** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
** memory to hold the resulting string.
**
** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
** the standard C library.  The result is written into the
** buffer supplied as the second parameter whose size is given by
** the first parameter. Note that the order of the
** first two parameters is reversed from snprintf().)^  This is an







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void sqlite3_free_table(char **result);

/*
** CAPI3REF: Formatted String Printing Functions
**
** These routines are work-alikes of the "printf()" family of functions
** from the standard C library.
** These routines understand most of the common formatting options from
** the standard library printf() 
** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).

** See the [built-in printf()] documentation for details.
**
** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
** results into memory obtained from [sqlite3_malloc64()].
** The strings returned by these two routines should be
** released by [sqlite3_free()].  ^Both routines return a
** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
** memory to hold the resulting string.
**
** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
** the standard C library.  The result is written into the
** buffer supplied as the second parameter whose size is given by
** the first parameter. Note that the order of the
** first two parameters is reversed from snprintf().)^  This is an
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** guarantees that the buffer is always zero-terminated.  ^The first
** parameter "n" is the total size of the buffer, including space for
** the zero terminator.  So the longest string that can be completely
** written will be n-1 characters.
**
** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
**
** These routines all implement some additional formatting
** options that are useful for constructing SQL statements.
** All of the usual printf() formatting options apply.  In addition, there
** is are "%q", "%Q", "%w" and "%z" options.
**
** ^(The %q option works like %s in that it substitutes a nul-terminated
** string from the argument list.  But %q also doubles every '\'' character.
** %q is designed for use inside a string literal.)^  By doubling each '\''
** character it escapes that character and allows it to be inserted into
** the string.
**
** For example, assume the string variable zText contains text as follows:
**
** <blockquote><pre>
**  char *zText = "It's a happy day!";
** </pre></blockquote>
**
** One can use this text in an SQL statement as follows:
**
** <blockquote><pre>
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
** </pre></blockquote>
**
** Because the %q format string is used, the '\'' character in zText
** is escaped and the SQL generated is as follows:
**
** <blockquote><pre>
**  INSERT INTO table1 VALUES('It''s a happy day!')
** </pre></blockquote>
**
** This is correct.  Had we used %s instead of %q, the generated SQL
** would have looked like this:
**
** <blockquote><pre>
**  INSERT INTO table1 VALUES('It's a happy day!');
** </pre></blockquote>
**
** This second example is an SQL syntax error.  As a general rule you should
** always use %q instead of %s when inserting text into a string literal.
**
** ^(The %Q option works like %q except it also adds single quotes around
** the outside of the total string.  Additionally, if the parameter in the
** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
** single quotes).)^  So, for example, one could say:
**
** <blockquote><pre>
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
** </pre></blockquote>
**
** The code above will render a correct SQL statement in the zSQL
** variable even if the zText variable is a NULL pointer.
**
** ^(The "%w" formatting option is like "%q" except that it expects to
** be contained within double-quotes instead of single quotes, and it
** escapes the double-quote character instead of the single-quote
** character.)^  The "%w" formatting option is intended for safely inserting
** table and column names into a constructed SQL statement.
**
** ^(The "%z" formatting option works like "%s" but with the
** addition that after the string has been read and copied into
** the result, [sqlite3_free()] is called on the input string.)^
*/
char *sqlite3_mprintf(const char*,...);
char *sqlite3_vmprintf(const char*, va_list);
char *sqlite3_snprintf(int,char*,const char*, ...);
char *sqlite3_vsnprintf(int,char*,const char*, va_list);

/*







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** guarantees that the buffer is always zero-terminated.  ^The first
** parameter "n" is the total size of the buffer, including space for
** the zero terminator.  So the longest string that can be completely
** written will be n-1 characters.
**
** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
**


** See also:  [built-in printf()], [printf() SQL function]






























































*/
char *sqlite3_mprintf(const char*,...);
char *sqlite3_vmprintf(const char*, va_list);
char *sqlite3_snprintf(int,char*,const char*, ...);
char *sqlite3_vsnprintf(int,char*,const char*, va_list);

/*