Convert a MIME Entity to multipart/alternative

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Demonstrates the Chilkat Mime.ConvertToMultipartAlt method, which wraps the current entity in a new outer multipart/alternative, making the original the first child. It takes no arguments.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Use this to add an alternate rendering to an existing message — for example, promoting a plain-text message so an HTML version can be added alongside it. The original content becomes the first (least-preferred) alternative, and you append the richer representation after it. As with the mixed conversion, message-level headers move to the new outer entity.

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#include <C_CkMime.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkMime mime;
    HCkMime htmlPart;

    success = FALSE;

    mime = CkMime_Create();
    success = CkMime_LoadMimeFile(mime,"qa_data/message.eml");
    if (success == FALSE) {
        printf("%s\n",CkMime_lastErrorText(mime));
        CkMime_Dispose(mime);
        return;
    }

    //  Wrap the current entity in a new outer multipart/alternative entity.  The original entity
    //  becomes the first child, ready for an alternate representation to be added.
    success = CkMime_ConvertToMultipartAlt(mime);
    if (success == FALSE) {
        printf("%s\n",CkMime_lastErrorText(mime));
        CkMime_Dispose(mime);
        return;
    }

    //  Add an alternative representation of the same content.
    htmlPart = CkMime_Create();
    success = CkMime_SetBodyFromHtml(htmlPart,"<html><body>HTML alternative.</body></html>");
    if (success == FALSE) {
        printf("%s\n",CkMime_lastErrorText(htmlPart));
        CkMime_Dispose(mime);
        CkMime_Dispose(htmlPart);
        return;
    }

    success = CkMime_AppendPart(mime,htmlPart);
    if (success == FALSE) {
        printf("%s\n",CkMime_lastErrorText(mime));
        CkMime_Dispose(mime);
        CkMime_Dispose(htmlPart);
        return;
    }

    printf("Number of parts: %d\n",CkMime_getNumParts(mime));


    CkMime_Dispose(mime);
    CkMime_Dispose(htmlPart);

    }