ECPG(1) PostgreSQL Client Applications ECPG(1)
ecpg - embedded SQL C preprocessor
ecpg [ option... ] file...
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 preferrably have the extension .pgc, in which case the extension will be
replaced by .c to determine the output file name. If the extension of the input file is
not .pgc, then the output file name is computed by appending .c to the full 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 the PostgreSQL Pro-
grammer's Guide for that.
ecpg accepts the following command-line arguments:
-c Automatically generate C code from SQL code. Currently, this works for EXEC SQL
Define a C preprocessor symbol.
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.
Specifies that ecpg should write all its output to the given filename.
-t Turn on autocommit of transactions. In this mode, each query is automatically com-
mitted unless it is inside an explicit transaction block. In the default mode,
queries are committed only when EXEC SQL COMMIT is issued.
-v Print additional information including the version and the include path.
Show a brief summary of the command usage, then exit.
Output version information, then exit.
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, one 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 flags -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).
If you have an embedded SQL C source file named prog1.pgc, you can create an executable
program using the following sequence of commands:
cc -I/usr/local/pgsql/include -c prog1.c
cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg
PostgreSQL Programmer's Guide for a more detailed description of the embedded SQL inter-
Application 2002-11-22 ECPG(1)