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Get started with C

This guide walks you through the steps to use a sample project, and then explains how to integrate the Pdftools SDK into your application with the C programming language.

tip

Try the Pdftools SDK without a license key for free.

Getting started with a sample project​

Learn how to use the Pdftools SDK using a C sample project and convert a PDF file to an image.

Prerequisites​

This sample project uses GCC toolset 4.8+ and CMake version 3.16 or higher.

Compile and run the sample​

  1. Download a sample project, and then unzip the file.

  2. In the command line, navigate to the root directory of the unzipped sample project and then run:

    cmake .

  3. Build the sample:

    cmake --build .

  4. The sample project contains a PDF file PdfPrimerWhitePaper.pdf. To render it in multi-page TIFF image format, run:

    ./pdftoolspdf2imgsimple PdfPrimerWhitePaper.pdf PdfPrimerWhitePaper.tiff

The code sample takes:

  • The input and output files are represented as a file name or a file path with the file name.
  • Both file paths (input and output) can be relative or absolute.

Review the following snippet with a placeholder and compare it to the last step of the previous procedure:

./pdftoolspdf2imgsimple INPUT_FILE OUTPUT_FILE
note

You can apply a similar procedure described in this tutorial for other code samples. For more information, see Code samples page.

Integrate the SDK into your application​

Integrate and initialize the Pdftools SDK into your application by following the instructions in the following sections.

Add the SDK to your project​

  1. Click the download link to get the latest version of the Pdftools SDK for C in a zip archive.

    Optional: For older Linux distributions running glibc 2.12+, download the SDK from a separate download.

  2. Unzip the file on your machine into a local directory recommended for your operating system. For example:

    C:\Program Files\PDF Tools AG\

    Included subdirectories are:

    SubdirectoryDescription
    ~Contains important information in the README.md file.
    libRuntime executable binaries and runtime import libraries:
    • win-x86\PdfToolsSdk.dll and win-x86\PdfToolsSdk.lib for 32-bit Windows.
    • win-x64\PdfToolsSdk.dll and win-x64\PdfToolsSdk.lib for 64-bit Windows.
    • win-arm64\PdfToolsSdk.dll and win-arm64\PdfToolsSdk.lib for 64-bit Windows ARM.
    includeHeader files to add to your C or C++ project. The main header PdfTools.h includes all the other headers.

  3. Optional: The native libraries must be available in your compiler’s library path. This step is only required if your build process doesn’t resolve it automatically:

    Add the lib\win-x64, lib\win-arm64 or lib\win-x86 subdirectory to the %PATH% environment variable.

Optional: Initialize the SDK​

Learn how to remove watermarked output of the Pdftools SDK using a valid license key.

tip

You can try the Pdftools SDK without a license key for free. This section is optional if you want to evaluate this SDK. Initialization only lets you remove watermarks added to output files.

Getting a license key

Contact the Pdftools sales team through the Contact page to get a full license. For additional information, review Pdftools SDK license management.

To remove watermarks, follow these steps:

  1. Locate your license key. For more information, review Find the license key.

  2. Before you call any function of the Pdftools SDK, first call the PdfTools_Sdk_Initialize function.

    GOTO_CLEANUP_IF_FALSE_PRINT_ERROR(PdfTools_Sdk_Initialize(_T("insert-license-key-here"), NULL),
                                         _T("Failed to set the license key. %s (ErrorCode: 0x%08x).\n"), szErrorBuff,
                                         PdfTools_GetLastError());

    Replace the insert-license-key-here with the value of your license key. Include the less-than (<) and greater-than (>) signs.

To get a code sample with the PdfTools_Sdk_Initialize function that you can use as a reference for your code, follow these steps:

  1. On the Code samples page, download and unzip a C code sample. For example: Download Convert PDF to image sample.
  2. Unzip the file, and then find the PdfTools_Sdk_Initialize function in the main C file of the sample. For example: Convert PDF to image sample includes PdfTools_Sdk_Initialize function in the pdftoolspdf2imgsimple.c file.
  3. Uncomment the function and replace insert-license-key-here with your license key.

Uninitialize the SDK​

After processing files with the Pdftools SDK, call the Uninitialize function to unload the library correctly:

// Uninitialize library
PdfTools_Uninitialize();

Implement your use case​

  • Find more use cases and sample projects on the Code samples page.
  • For more technical information about the Pdftools SDK for C, consult the C technical notes.
  • If you need to configure a proxy, review Configure proxy documentation section.