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ECPG(1) PostgreSQL 9.2.24 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. Input files preferably have the extension .pgc. The extension will be replaced by .c
to determine the output file name. The output file name can also be overridden using the
-o option.
This reference page does not describe the embedded SQL language. See Chapter 33, ECPG -
Embedded SQL in C, in the documentation 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 or INFORMIX_SE.
-D symbol
Define a C preprocessor symbol.
-h
Parse a header file, this option includes otion -c.
-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.
-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.
--regression
Run in regression testing mode.
-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 9.2.24 2017-11-06 ECPG(1)
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