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MySQL 5.1 Plugin Development

You're reading from   MySQL 5.1 Plugin Development Extend MySQL to suit your needs with this unique guide into the world of MySQL plugins

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Product type Paperback
Published in Aug 2010
Publisher Packt
ISBN-13 9781849510608
Length 288 pages
Edition 1st Edition
Tools
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Toc

Table of Contents (16) Chapters Close

MySQL 5.1 Plugin Development
Credits
About the Authors
About the Reviewer
1. Preface
1. Compiling and Using MySQL Plugins 2. User Defined Functions FREE CHAPTER 3. Daemon Plugins 4. Information Schema Plugins 5. Advanced Information Schema Plugins 6. Full-text Parser Plugins 7. Practical Full-text Parsers 8. Storage Engine Plugins 9. HTML Storage Engine—Reads and Writes 10. TOCAB Storage Engine — Implementing Indexes Beyond MySQL 5.1

A simple static text output UDF


Returning text in a MySQL UDF can be slightly more complex than dealing with numbers. MySQL gives us a memory buffer to use when returning a string but it is only 766 bytes long. This is fine for some tasks, but not big enough to hold a long string or a blob, so what we do is allocate our own buffer for this purpose. Either way, we need to tell MySQL how long the resulting string is.

The next piece of example code has two UDFs inside it, the first showing how to use the memory buffer that MySQL has given us and the second allocating its own memory. Both are simple UDFs which will just return the MySQL version number that UDF was compiled against:

#include <stdlib.h>
#include <string.h>
#include <mysql.h>
my_bool udf_textexample_init(UDF_INIT *initid,
UDF_ARGS *args, char *message)
{
initid->const_item = 1;
return 0;
}

As with previous examples we create the initialization function. We set initid->const_item to 1 here because the return...

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MySQL 5.1 Plugin Development
Published in: Aug 2010
Publisher: Packt
ISBN-13: 9781849510608
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