Creating a Memory Buffer as a FILE* for Output in TiXml

In certain scenarios, the ability to write TiXml output to a memory buffer instead of a file can be useful. However, there is no direct functionality in TiXml to handle this.

Solution: Using POSIX Functions

To overcome this limitation, POSIX provides two functions that enable you to create a memory buffer as a FILE*:

• fmemopen: Creates a FILE* object from an existing memory buffer.
• open_memstream: Creates a memory buffer and FILE* object simultaneously.

Example Using fmemopen:

#include 

void writeXmlToMemoryBuffer(TiXmlDocument& doc) {
    // Create a memory buffer
    char buffer[1024];

    // Open the buffer as a FILE* object
    FILE* fp = fmemopen(buffer, sizeof(buffer), "w");

    // Write the XML document to the memory buffer through the FILE* object
    doc.Print(fp);

    // Close the FILE* object
    fclose(fp);
}

In this example, the fmemopen function takes the memory buffer buffer and its size as arguments, along with the file mode "w" for writing. The doc.Print method then writes the XML document to the memory buffer via the fp FILE* object.

Example Using open_memstream:

#include 
#include 

void writeXmlToMemoryBuffer(TiXmlDocument& doc) {
    std::ostringstream buffer;
    doc.Print(&buffer);
    std::cout 
In this example, the open_memstream function is not explicitly used, but the sstream library provides similar functionality. It creates a string buffer object (buffer) and a FILE object (&buffer) simultaneously. The doc.Print method writes the XML document to the memory buffer through the FILE object. The contents of the memory buffer can then be accessed as a string.
By using these POSIX functions, you can effectively create a memory buffer that behaves like a FILE* object, allowing TiXml to output XML directly to the memory buffer.