MLCreateMark()

#include "mathlink.h"

/* check for a ReturnPacket and go back in the expression stream if necessary */

void f(MLINK lp)
{
    MLMARK mark;
    int args;

    mark = MLCreateMark(lp);
    if(mark == (MLMARK)0)
        { /* mark creation failed */ }

    if(! MLTestHead(lp, "ReturnPacket", args))
        {
            MLSeekToMark(lp, mark, 0);
            MLDestroyMark(lp, mark);
        }
    else
        { /* read the ReturnPacket[] */ }
}