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ecpg(1)                  PostgreSQL 12.3 Documentation                 ecpg(1)




NAME

       ecpg - embedded SQL C preprocessor


SYNOPSIS

       ecpg [option...] file...


DESCRIPTION

       ecpg is the embedded SQL preprocessor for C programs. It converts C
       programs with embedded SQL statements to normal C code by replacing the
       SQL invocations with special function calls. The output files can then
       be processed with any C compiler tool chain.

       ecpg will convert each input file given on the command line to the
       corresponding C output file. If an input file name does not have any
       extension, .pgc is assumed. The file's extension will be replaced by .c
       to construct the output file name. But the output file name can be
       overridden using the -o option.

       If an input file name is just -, ecpg reads the program from standard
       input (and writes to standard output, unless that is overridden with
       -o).

       This reference page does not describe the embedded SQL language. See
       Chapter 35 for more information on that topic.


OPTIONS

       ecpg accepts the following command-line arguments:

       -c
           Automatically generate certain C code from SQL code. Currently,
           this works for EXEC SQL TYPE.

       -C mode
           Set a compatibility mode.  mode can be INFORMIX, INFORMIX_SE, or
           ORACLE.

       -D symbol
           Define a C preprocessor symbol.

       -h
           Process header files. When this option is specified, the output
           file extension becomes .h not .c, and the default input file
           extension is .pgh not .pgc. Also, the -c option is forced on.

       -i
           Parse system include files as well.

       -I directory
           Specify an additional include path, used to find files included via
           EXEC SQL INCLUDE. Defaults are .  (current directory),
           /usr/local/include, the PostgreSQL include directory which is
           defined at compile time (default: /usr/local/pgsql/include), and
           /usr/include, in that order.

       -o filename
           Specifies that ecpg should write all its output to the given
           filename. Write -o - to send all output to standard output.

       -r option
           Selects run-time behavior.  Option can be one of the following:

           no_indicator
               Do not use indicators but instead use special values to
               represent null values. Historically there have been databases
               using this approach.

           prepare
               Prepare all statements before using them. Libecpg will keep a
               cache of prepared statements and reuse a statement if it gets
               executed again. If the cache runs full, libecpg will free the
               least used statement.

           questionmarks
               Allow question mark as placeholder for compatibility reasons.
               This used to be the default long ago.

       -t
           Turn on autocommit of transactions. In this mode, each SQL command
           is automatically committed unless it is inside an explicit
           transaction block. In the default mode, commands are committed only
           when EXEC SQL COMMIT is issued.

       -v
           Print additional information including the version and the
           "include" path.

       --version
           Print the ecpg version and exit.

       -?
       --help
           Show help about ecpg command line arguments, and exit.


NOTES

       When compiling the preprocessed C code files, the compiler needs to be
       able to find the ECPG header files in the PostgreSQL include directory.
       Therefore, you might have to use the -I option when invoking the
       compiler (e.g., -I/usr/local/pgsql/include).

       Programs using C code with embedded SQL have to be linked against the
       libecpg library, for example using the linker options
       -L/usr/local/pgsql/lib -lecpg.

       The value of either of these directories that is appropriate for the
       installation can be found out using pg_config(1).


EXAMPLES

       If you have an embedded SQL C source file named prog1.pgc, you can
       create an executable program using the following sequence of commands:

           ecpg prog1.pgc
           cc -I/usr/local/pgsql/include -c prog1.c
           cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg




PostgreSQL 12.3                      2020                              ecpg(1)

postgresql 12.3 - Generated Tue May 26 08:27:50 CDT 2020
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