MLSeekToMark()

#include "mathlink.h"

/* look ahead in the expression stream on a link and reset */

void f(MLINK lp)
{
    MLMARK mark;
    
    mark = MLCreateMark(lp);
    if(mark == (MLMARK)0)
        { /* unable to create mark in the stream on lp */ }

    /* now peek ahead and see what is coming */
    switch(MLGetNext(lp))
    {
        case MLTKINT:
            /* integer data */
        case MLTKREAL:
            /* floating-point data */
    }

    /* now restore to the original point */
    mark = MLSeekToMark(lp, mark, 0);
    if(mark == (MLMARK)0)
        { /* unable to seek to the mark position in lp */ }

    MLDestroyMark(lp, mark);
}