doc/src/sgml/ref/ecpg-ref.sgml

   1 <!--
   2 $PostgreSQL$
   3 PostgreSQL documentation
   4 -->
   5
   6 <refentry id="APP-ECPG">
   7  <refmeta>
   8   <refentrytitle><application>ecpg</application></refentrytitle>
   9   <manvolnum>1</manvolnum>
  10   <refmiscinfo>Application</refmiscinfo>
  11  </refmeta>
  12
  13  <refnamediv>
  14   <refname><application>ecpg</application></refname>
  15   <refpurpose>embedded SQL C preprocessor</refpurpose>
  16  </refnamediv>
  17
  18  <indexterm zone="app-ecpg">
  19   <primary>ecpg</primary>
  20  </indexterm>
  21
  22  <refsynopsisdiv>
  23   <cmdsynopsis>
  24    <command>ecpg</command>
  25    <arg choice="opt" rep="repeat"><replaceable>option</replaceable></arg>
  26    <arg choice="plain" rep="repeat"><replaceable>file</replaceable></arg>
  27   </cmdsynopsis>
  28  </refsynopsisdiv>
  29
  30
  31  <refsect1 id="APP-ECPG-description">
  32   <title>Description</title>
  33
  34   <para>
  35    <command>ecpg</command> is the embedded SQL preprocessor for C
  36    programs.  It converts C programs with embedded SQL statements to
  37    normal C code by replacing the SQL invocations with special
  38    function calls.  The output files can then be processed with any C
  39    compiler tool chain.
  40   </para>
  41
  42   <para>
  43    <command>ecpg</command> will convert each input file given on the
  44    command line to the corresponding C output file.  Input files
  45    preferably have the extension <filename>.pgc</filename>, in which
  46    case the extension will be replaced by <filename>.c</filename> to
  47    determine the output file name.  If the extension of the input file
  48    is not <filename>.pgc</filename>, then the output file name is
  49    computed by appending <literal>.c</literal> to the full file name.
  50    The output file name can also be overridden using the
  51    <option>-o</option> option.
  52   </para>
  53
  54   <para>
  55    This reference page does not describe the embedded SQL language.
  56    See <xref linkend="ecpg"> for more information on that topic.
  57   </para>
  58  </refsect1>
  59
  60
  61  <refsect1>
  62   <title>Options</title>
  63
  64   <para>
  65    <command>ecpg</command> accepts the following command-line
  66    arguments:
  67
  68    <variablelist>
  69     <varlistentry>
  70      <term><option>-c</option></term>
  71      <listitem>
  72       <para>
  73        Automatically generate certain C code from SQL code.  Currently, this
  74        works for <literal>EXEC SQL TYPE</literal>.
  75       </para>
  76      </listitem>
  77     </varlistentry>
  78
  79     <varlistentry>
  80      <term><option>-C <replaceable>mode</replaceable></option></term>
  81      <listitem>
  82       <para>
  83        Set a compatibility mode.  <replaceable>mode</replaceable> can
  84        be <literal>INFORMIX</literal> or
  85        <literal>INFORMIX_SE</literal>.
  86       </para>
  87      </listitem>
  88     </varlistentry>
  89
  90     <varlistentry>
  91      <term><option>-D <replaceable>symbol</replaceable></option></term>
  92      <listitem>
  93       <para>
  94        Define a C preprocessor symbol.
  95       </para>
  96      </listitem>
  97     </varlistentry>
  98
  99     <varlistentry>
 100      <term><option>-i</option></term>
 101      <listitem>
 102       <para>
 103        Parse system include files as well.
 104       </para>
 105      </listitem>
 106     </varlistentry>
 107
 108     <varlistentry>
 109      <term><option>-I <replaceable class="parameter">directory</replaceable></option></term>
 110      <listitem>
 111       <para>
 112        Specify an additional include path, used to find files included
 113        via <literal>EXEC SQL INCLUDE</literal>.  Defaults are
 114        <filename>.</filename> (current directory),
 115        <filename>/usr/local/include</filename>, the
 116        <productname>PostgreSQL</productname> include directory which
 117        is defined at compile time (default:
 118        <filename>/usr/local/pgsql/include</filename>), and
 119        <filename>/usr/include</filename>, in that order.
 120       </para>
 121      </listitem>
 122     </varlistentry>
 123
 124     <varlistentry>
 125      <term><option>-o <replaceable>filename</replaceable></option></term>
 126      <listitem>
 127       <para>
 128        Specifies that <command>ecpg</command> should write all
 129        its output to the given <replaceable>filename</replaceable>.
 130       </para>
 131      </listitem>
 132     </varlistentry>
 133
 134     <varlistentry>
 135      <term><option>-r <replaceable>option</replaceable></option></term>
 136      <listitem>
 137       <para>
 138        Selects a run-time behavior.  Currently,
 139        <replaceable>option</replaceable> can only be
 140        <literal>no_indicator</literal>.
 141       </para>
 142      </listitem>
 143     </varlistentry>
 144
 145     <varlistentry>
 146      <term><option>-t</option></term>
 147      <listitem>
 148       <para>
 149        Turn on autocommit of transactions. In this mode, each SQL command is
 150        automatically committed unless it is inside an explicit
 151        transaction block. In the default mode, commands are committed
 152        only when <command>EXEC SQL COMMIT</command> is issued.
 153       </para>
 154      </listitem>
 155     </varlistentry>
 156
 157     <varlistentry>
 158      <term><option>-v</option></term>
 159      <listitem>
 160       <para>
 161        Print additional information including the version and the
 162        include path.
 163       </para>
 164      </listitem>
 165     </varlistentry>
 166
 167     <varlistentry>
 168      <term><option>--help</option></term>
 169      <listitem>
 170       <para>
 171        Show a brief summary of the command usage, then exit.
 172       </para>
 173      </listitem>
 174     </varlistentry>
 175
 176     <varlistentry>
 177      <term><option>--version</option></term>
 178      <listitem>
 179       <para>
 180        Output version information, then exit.
 181       </para>
 182      </listitem>
 183     </varlistentry>
 184    </variablelist>
 185   </para>
 186  </refsect1>
 187
 188
 189  <refsect1>
 190   <title>Notes</title>
 191
 192   <para>
 193    When compiling the preprocessed C code files, the compiler needs to
 194    be able to find the <application>ECPG</> header files in the
 195    <productname>PostgreSQL</> include directory.  Therefore, one might
 196    have to use the <option>-I</> option when invoking the compiler
 197    (e.g., <literal>-I/usr/local/pgsql/include</literal>).
 198   </para>
 199
 200   <para>
 201    Programs using C code with embedded SQL have to be linked against
 202    the <filename>libecpg</filename> library, for example using the
 203    linker options <literal>-L/usr/local/pgsql/lib -lecpg</literal>.
 204   </para>
 205
 206   <para>
 207    The value of either of these directories that is appropriate for
 208    the installation can be found out using <xref
 209    linkend="app-pgconfig">.
 210   </para>
 211  </refsect1>
 212
 213
 214  <refsect1>
 215   <title>Examples</title>
 216
 217   <para>
 218    If you have an embedded SQL C source file named
 219    <filename>prog1.pgc</filename>, you can create an executable
 220    program using the following sequence of commands:
 221 <programlisting>
 222 ecpg prog1.pgc
 223 cc -I/usr/local/pgsql/include -c prog1.c
 224 cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg
 225 </programlisting>
 226   </para>
 227  </refsect1>
 228
 229 </refentry>