1ECPG(1) PostgreSQL 10.7 Documentation ECPG(1)
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6 ecpg - embedded SQL C preprocessor
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9 ecpg [option...] file...
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12 ecpg is the embedded SQL preprocessor for C programs. It converts C
13 programs with embedded SQL statements to normal C code by replacing the
14 SQL invocations with special function calls. The output files can then
15 be processed with any C compiler tool chain.
16 ecpg will convert each input file given on the command line to the
18 corresponding C output file. Input files preferably have the extension
19 .pgc. The extension will be replaced by .c to determine the output file
20 name. The output file name can also be overridden using the -o option.
21 This reference page does not describe the embedded SQL language. See
23 Chapter 35 for more information on that topic.
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26 ecpg accepts the following command-line arguments:
27 -c
29 Automatically generate certain C code from SQL code. Currently,
30 this works for EXEC SQL TYPE.
31 -C mode
33 Set a compatibility mode. mode can be INFORMIX or INFORMIX_SE.
34 -D symbol
36 Define a C preprocessor symbol.
37 -h
39 Parse a header file, this option includes option -c.
40 -i
42 Parse system include files as well.
43 -I directory
45 Specify an additional include path, used to find files included via
46 EXEC SQL INCLUDE. Defaults are . (current directory),
47 /usr/local/include, the PostgreSQL include directory which is
48 defined at compile time (default: /usr/local/pgsql/include), and
49 /usr/include, in that order.
50 -o filename
52 Specifies that ecpg should write all its output to the given
53 filename.
54 -r option
56 Selects run-time behavior. Option can be one of the following:
57 no_indicator
59 Do not use indicators but instead use special values to
60 represent null values. Historically there have been databases
61 using this approach.
62 prepare
64 Prepare all statements before using them. Libecpg will keep a
65 cache of prepared statements and reuse a statement if it gets
66 executed again. If the cache runs full, libecpg will free the
67 least used statement.
68 questionmarks
70 Allow question mark as placeholder for compatibility reasons.
71 This used to be the default long ago.
72 --regression
74 Run in regression testing mode.
75 -t
77 Turn on autocommit of transactions. In this mode, each SQL command
78 is automatically committed unless it is inside an explicit
79 transaction block. In the default mode, commands are committed only
80 when EXEC SQL COMMIT is issued.
81 -v
83 Print additional information including the version and the
84 "include" path.
85 --version
87 Print the ecpg version and exit.
88 -?
90 --help
91 Show help about ecpg command line arguments, and exit.
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94 When compiling the preprocessed C code files, the compiler needs to be
95 able to find the ECPG header files in the PostgreSQL include directory.
96 Therefore, you might have to use the -I option when invoking the
97 compiler (e.g., -I/usr/local/pgsql/include).
98 Programs using C code with embedded SQL have to be linked against the
100 libecpg library, for example using the linker options
101 -L/usr/local/pgsql/lib -lecpg.
102 The value of either of these directories that is appropriate for the
104 installation can be found out using pg_config(1).
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107 If you have an embedded SQL C source file named prog1.pgc, you can
108 create an executable program using the following sequence of commands:
109 ecpg prog1.pgc
111 cc -I/usr/local/pgsql/include -c prog1.c
112 cc -o prog1 prog1.o -L/usr/local/pgsql/lib -lecpg
113PostgreSQL 10.7 2019 ECPG(1)