FPDF_CloseDocument

FPDF_CloseDocument(document)

Description

Closes a PDF document and releases all resources associated with it. This function must be called when you’re done with a PDF document that was opened with FPDF_LoadMemDocument, FPDF_LoadCustomDocument, or any other document loading function.

Failing to call this function will result in memory leaks in your application.

Prerequisites

This example uses the initializePdfium helper function from our Getting Started guide. Make sure to include this function in your code before trying the examples below.

Parameters

Name	Type	Description
document	number	A document handle obtained from `FPDF_LoadMemDocument` or other document loading functions.

Return Value

This function does not return a value.

Example


// Note: The initializePdfium function is a helper that initializes the PDFium library.
// For the full implementation, see: /docs/pdfium/getting-started
import { init, WrappedPdfiumModule } from '@embedpdf/pdfium';
 
// Singleton for PDFium instance
let pdfiumInstance: WrappedPdfiumModule | null = null;
 
async function getPdfiumInstance() {
  if (pdfiumInstance) return pdfiumInstance;
  
  const response = await fetch('https://cdn.jsdelivr.net/npm/@embedpdf/pdfium/dist/pdfium.wasm');
  const wasmBinary = await response.arrayBuffer();
  pdfiumInstance = await init({ wasmBinary });
  
  // Initialize the PDFium extension library
  pdfiumInstance.PDFiumExt_Init();
  
  return pdfiumInstance;
}
 
async function openAndClosePdf(pdfData: Uint8Array) {
  // Get PDFium instance
  const pdfium = await getPdfiumInstance();
  
  // Allocate memory for the PDF data
  const filePtr = pdfium.pdfium.wasmExports.malloc(pdfData.length);
  
  try {
    // Copy the PDF data to the allocated memory
    pdfium.pdfium.HEAPU8.set(pdfData, filePtr);
    
    // Load the PDF document
    const docPtr = pdfium.FPDF_LoadMemDocument(filePtr, pdfData.length, 0);
    
    if (!docPtr) {
      const error = pdfium.FPDF_GetLastError();
      throw new Error(`Failed to load PDF: ${error}`);
    }
    
    try {
      // Do operations with the PDF...
      const pageCount = pdfium.FPDF_GetPageCount(docPtr);
      console.log(`PDF has ${pageCount} pages`);
      
      // More PDF operations...
      
    } finally {
      // Always close the document when done
      pdfium.FPDF_CloseDocument(docPtr);
      console.log('PDF document closed successfully');
    }
  } finally {
    // Always free the memory allocated for the PDF data
    pdfium.pdfium.wasmExports.free(filePtr);
  }
}
 
// Usage
fetch('sample.pdf')
  .then(response => response.arrayBuffer())
  .then(buffer => openAndClosePdf(new Uint8Array(buffer)))
  .catch(error => {
    console.error('Error:', error);
  });

Best Practices

Always close documents: Call FPDF_CloseDocument for every document you open, even if operations on the document fail. This prevents memory leaks.
Use try/finally blocks: Place your document operations inside a try block and the FPDF_CloseDocument call in a finally block to ensure the document is closed even if exceptions occur.
Close in the correct order: If you have opened multiple resources (e.g., pages, text pages) from a document, close them in the reverse order before closing the document:
- Close text pages with FPDFText_ClosePage
- Close pages with FPDF_ClosePage
- Finally, close the document with FPDF_CloseDocument
Don’t use the document after closing: After calling FPDF_CloseDocument, the document handle is no longer valid. Any attempts to use it will result in undefined behavior and likely crashes.

FPDF_LoadMemDocument - Load a PDF document from memory