## J.3. Building the Documentation

Once you have everything set up, change to the directory `doc/src/sgml` and run one of the commands described in the following subsections to build the documentation. (Remember to use GNU make.)

### J.3.1. HTML

To build the HTML version of the documentation:

    doc/src/sgml$ make html

This is also the default target. The output appears in the subdirectory `html`.

To produce HTML documentation with the stylesheet used on postgresql.org instead of the default simple style use:

    doc/src/sgml$ make STYLE=website html

If the `STYLE=website` option is used, the generated HTML files include references to stylesheets hosted on postgresql.org and require network access to view.

### J.3.2. Manpages

We use the DocBook XSL stylesheets to convert DocBook `refentry` pages to *roff output suitable for man pages. To create the man pages, use the command:

    doc/src/sgml$ make man

### J.3.3. PDF

To produce a PDF rendition of the documentation using FOP, you can use one of the following commands, depending on the preferred paper format:

- For A4 format:

      doc/src/sgml$ make postgres-A4.pdf

- For U.S. letter format:

      doc/src/sgml$ make postgres-US.pdf

Because the PostgreSQL documentation is fairly big, FOP will require a significant amount of memory. Because of that, on some systems, the build will fail with a memory-related error message. This can usually be fixed by configuring Java heap settings in the configuration file `~/.foprc`, for example:

    # FOP binary distribution
    FOP_OPTS='-Xmx1500m'
    # Debian
    JAVA_ARGS='-Xmx1500m'
    # Red Hat
    ADDITIONAL_FLAGS='-Xmx1500m'

There is a minimum amount of memory that is required, and to some extent more memory appears to make things a bit faster. On systems with very little memory (less than 1 GB), the build will either be very slow due to swapping or will not work at all.

Other XSL-FO processors can also be used manually, but the automated build process only supports FOP.

### J.3.4. Plain Text Files

The installation instructions are also distributed as plain text, in case they are needed in a situation where better reading tools are not available. The `INSTALL` file corresponds to Chapter 16, with some minor changes to account for the different context. To recreate the file, change to the directory `doc/src/sgml` and enter `make INSTALL`. Building text output requires Pandoc version 1.13 or newer as an additional build tool.

In the past, the release notes and regression testing instructions were also distributed as plain text, but this practice has been discontinued.

### J.3.5. Syntax Check

Building the documentation can take very long. But there is a method to just check the correct syntax of the documentation files, which only takes a few seconds:

    doc/src/sgml$ make check