Function textmark is similar to mark but draw text instead of markers.
MGL code:
call 'prepare1d' subplot 1 1 0 '':title 'TextMark plot (default)':box:textmark y y1 '\gamma' 'r'
C++ code:
void smgl_textmark(mglGraph *gr)
{
mglData y,y1; mgls_prepare1d(&y,&y1);
if(big!=3) { gr->SubPlot(1,1,0,""); gr->Title("TextMark plot (default)"); }
gr->Box(); gr->TextMark(y,y1,"\\gamma","r");
}