Equivalent C Types for Built-in SQL Types in PostgreSQL (Part 1)

27th chunk of `doc/src/sgml/xfunc.sgml`

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 type definition.  (The actual
     definition might be in a different file that is included by the
     listed file.  It is recommended that users stick to the defined
     interface.)  Note that you should always include
     <filename>postgres.h</filename> first in any source file of server
     code, because it declares a number of things that you will need
     anyway, and because including other headers first can cause
     portability issues.
    </para>

     <table tocentry="1" id="xfunc-c-type-table">
      <title>Equivalent C Types for Built-in SQL Types</title>
      <tgroup cols="3">
       <colspec colname="col1" colwidth="1*"/>
       <colspec colname="col2" colwidth="1*"/>
       <colspec colname="col3" colwidth="2*"/>
       <thead>
        <row>
         <entry>
          SQL Type
         </entry>
         <entry>
          C Type
         </entry>
         <entry>
          Defined In
         </entry>
        </row>
       </thead>
       <tbody>
        <row>
         <entry><type>boolean</type></entry>
         <entry><type>bool</type></entry>
         <entry><filename>postgres.h</filename> (maybe compiler built-in)</entry>
        </row>
        <row>
         <entry><type>box</type></entry>
         <entry><type>BOX*</type></entry>
         <entry><filename>utils/geo_decls.h</filename></entry>
        </row>
        <row>
         <entry><type>bytea</type></entry>
         <entry><type>bytea*</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>"char"</type></entry>
         <entry><type>char</type></entry>
         <entry>(compiler built-in)</entry>
        </row>
        <row>
         <entry><type>character</type></entry>
         <entry><type>BpChar*</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>cid</type></entry>
         <entry><type>CommandId</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>date</type></entry>
         <entry><type>DateADT</type></entry>
         <entry><filename>utils/date.h</filename></entry>
        </row>
        <row>
         <entry><type>float4</type> (<type>real</type>)</entry>
         <entry><type>float4</type></entry>
        <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>float8</type> (<type>double precision</type>)</entry>
         <entry><type>float8</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>int2</type> (<type>smallint</type>)</entry>
         <entry><type>int16</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>int4</type> (<type>integer</type>)</entry>
         <entry><type>int32</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>int8</type> (<type>bigint</type>)</entry>
         <entry><type>int64</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>interval</type></entry>
         <entry><type>Interval*</type></entry>
         <entry><filename>datatype/timestamp.h</filename></entry>
        </row>
        <row>
         <entry><type>lseg</type></entry>
         <entry><type>LSEG*</type></entry>
         <entry><filename>utils/geo_decls.h</filename></entry>
        </row>
        <row>
         <entry><type>name</type></entry>
         <entry><type>Name</type></entry>
         <entry><filename>postgres.h</filename></entry>
        </row>
        <row>
         <entry><type>numeric</type></entry>
         <entry><type>Numeric</type></entry>
         <entry><filename>utils/numeric.h</filename></entry>
        </row>
        <row>
         <entry><type>oid</type></entry>
         <entry><type>Oid</type></entry>

Title: Equivalent C Types for Built-in SQL Types in PostgreSQL (Part 1)

Summary

This section details the equivalent C types for various built-in SQL data types in PostgreSQL. It lists SQL types like boolean, box, bytea, char, character, cid, date, float4, float8, int2, int4, int8, interval, lseg, name, numeric, and oid along with their corresponding C types and the header files where they are defined. The text advises to include postgres.h first in any server code source file and emphasizes that users should stick to the defined interface.