PDFio is a simple C library for reading and writing PDF files. The primary goals of PDFio are:

• Read and write any version of PDF file
• Provide access to pages, objects, and streams within a PDF file
• Support reading and writing of encrypted PDF files
• Extract or embed useful metadata (author, creator, page information, etc.)
• "Filter" PDF files, for example to extract a range of pages or to embed fonts that are missing from a PDF
• Provide access to objects used for each page

PDFio is not concerned with rendering or viewing a PDF file, although a PDF RIP or viewer could be written using it.

PDFio requires the following to build the software:

• A C99 compiler such as Clang, GCC, or MS Visual C
• A POSIX-compliant make program
• ZLIB (https://www.zlib.net) 1.1 or higher

IDE files for Xcode (macOS/iOS) and Visual Studio (Windows) are also provided.

See the man page (pdfio.3) and full HTML documentation (pdfio.html) for information on using PDFio.

PDFio uses a configure script on Unix systems to generate a makefile:

./configure

If you want a shared library, run:

./configure --enable-shared

The default installation location is "/usr/local". Pass the --prefix option to make to install it to another location:

./configure --prefix=/some/other/directory

Once configured, run the following to make the library:

make all

To test it, run:

make test

To install it, run:

sudo make install

The Visual Studio solution ("pdfio.sln") is provided for Windows developers and generates the PDFIO1 DLL. You can also use NuGet to install the pdfio_native package.

There is also an Xcode project ("pdfio.xcodeproj") you can use on macOS which generates a static library that will be installed under "/usr/local" with:

sudo xcodebuild install

PDFio is Copyright © 2021-2025 by Michael R Sweet.

This software is licensed under the Apache License Version 2.0 with an (optional) exception to allow linking against GPL2/LGPL2 software. See the files "LICENSE" and "NOTICE" for more information.