<literal>sqlca.sqlerrm.sqlerrml</literal> contains the length of
    the error message that is stored in
    <literal>sqlca.sqlerrm.sqlerrmc</literal> (the result of
    <function>strlen()</function>, not really interesting for a C
    programmer).  Note that some messages are too long to fit in the
    fixed-size <literal>sqlerrmc</literal> array; they will be truncated.
   </para>

   <para>
    In case of a warning, <literal>sqlca.sqlwarn[2]</literal> is set
    to <literal>W</literal>.  (In all other cases, it is set to
    something different from <literal>W</literal>.)  If
    <literal>sqlca.sqlwarn[1]</literal> is set to
    <literal>W</literal>, then a value was truncated when it was
    stored in a host variable.  <literal>sqlca.sqlwarn[0]</literal> is
    set to <literal>W</literal> if any of the other elements are set
    to indicate a warning.
   </para>

   <para>
    The fields <structfield>sqlcaid</structfield>,
    <structfield>sqlabc</structfield>,
    <structfield>sqlerrp</structfield>, and the remaining elements of
    <structfield>sqlerrd</structfield> and
    <structfield>sqlwarn</structfield> currently contain no useful
    information.
   </para>

   <para>
    The structure <varname>sqlca</varname> is not defined in the SQL
    standard, but is implemented in several other SQL database
    systems.  The definitions are similar at the core, but if you want
    to write portable applications, then you should investigate the
    different implementations carefully.
   </para>

   <para>
    Here is one example that combines the use of <literal>WHENEVER</literal>
    and <varname>sqlca</varname>, printing out the contents
    of <varname>sqlca</varname> when an error occurs.  This is perhaps
    useful for debugging or prototyping applications, before
    installing a more <quote>user-friendly</quote> error handler.

<programlisting>
EXEC SQL WHENEVER SQLERROR CALL print_sqlca();

void
print_sqlca()
{
    fprintf(stderr, "==== sqlca ====\n");
    fprintf(stderr, "sqlcode: %ld\n", sqlca.sqlcode);
    fprintf(stderr, "sqlerrm.sqlerrml: %d\n", sqlca.sqlerrm.sqlerrml);
    fprintf(stderr, "sqlerrm.sqlerrmc: %s\n", sqlca.sqlerrm.sqlerrmc);
    fprintf(stderr, "sqlerrd: %ld %ld %ld %ld %ld %ld\n", sqlca.sqlerrd[0],sqlca.sqlerrd[1],sqlca.sqlerrd[2],
                                                          sqlca.sqlerrd[3],sqlca.sqlerrd[4],sqlca.sqlerrd[5]);
    fprintf(stderr, "sqlwarn: %d %d %d %d %d %d %d %d\n", sqlca.sqlwarn[0], sqlca.sqlwarn[1], sqlca.sqlwarn[2],
                                                          sqlca.sqlwarn[3], sqlca.sqlwarn[4], sqlca.sqlwarn[5],
                                                          sqlca.sqlwarn[6], sqlca.sqlwarn[7]);
    fprintf(stderr, "sqlstate: %5s\n", sqlca.sqlstate);
    fprintf(stderr, "===============\n");
}
</programlisting>

    The result could look as follows (here an error due to a
    misspelled table name):

<screen>
==== sqlca ====
sqlcode: -400
sqlerrm.sqlerrml: 49
sqlerrm.sqlerrmc: relation "pg_databasep" does not exist on line 38
sqlerrd: 0 0 0 0 0 0
sqlwarn: 0 0 0 0 0 0 0 0
sqlstate: 42P01
===============
</screen>
   </para>
  </sect2>

  <sect2 id="ecpg-sqlstate-sqlcode">
   <title><literal>SQLSTATE</literal> vs. <literal>SQLCODE</literal></title>

   <para>
    The fields <literal>sqlca.sqlstate</literal> and
    <literal>sqlca.sqlcode</literal> are two different schemes that
    provide error codes.  Both are derived from the SQL standard, but
    <literal>SQLCODE</literal> has been marked deprecated in the SQL-92
    edition of the standard and has been dropped in later editions.
    Therefore, new applications are strongly encouraged to use
    <literal>SQLSTATE</literal>.
   </para>

   <para>
    <literal>SQLSTATE</literal> is a five-character array.  The five
    characters contain digits or upper-case letters that represent
    codes of various error and warning conditions.
    <literal>SQLSTATE</literal> has a hierarchical scheme: