The following document fails with pdfTeX 3.1415926-2.5-1.40.14 (MiKTeX 2.9), 64bit version:
\documentclass{article}
\begin{document}
Hello
\pdfsetmatrix{2.0 0.0 0.0 2.0}
World
\end{document}
It works without dots: \pdfsetmatrix{2 0 0 2}.
The correponding source code lines come from pdftexdir/utils.c in function pdfsetmatrix:
typedef struct {
double a;
double b;
double c;
double d;
double e;
double f;
} matrix_entry;
...
integer pdfsetmatrix(poolpointer in, scaled cur_h, scaled cur_v)
{
matrix_entry x, *y, *z;
char dummy;
if (page_mode) {
if (sscanf((const char *) &strpool[in], " %lf %lf %lf %lf %c",
&x.a, &x.b, &x.c, &x.d, &dummy) != 4) {
return 0; /* failure */
}
...
}
It seems that sscanf behaves differently for the 64bit version.
The bug was found by Acrofales (see TeX.SX question (tex.stackexchange.com). In my answer I gave an analysis as far as I could go without having the "right" OS.
