Hi, While debugging luatex, I ran into this warning from valgrind that seems to affect regular pdftex as well: ==4016== Conditional jump or move depends on uninitialised value(s) ==4016== at 0x80F851B: longest_match (deflate.c:1143) ==4016== by 0x80F9848: deflate_slow (deflate.c:1595) ==4016== by 0x80F8D98: deflate (deflate.c:790) ==4016== by 0x80DAE88: write_zip (writezip.c:58) ==4016== by 0x80729A2: pdf_flush (luatex1.c:10926) ==4016== by 0x80757BD: pdf_end_stream (luatex1.c:11068) ==4016== by 0x809AA68: zpdf_ship_out (luatex2.c:2057) ==4016== by 0x809C913: zship_out (luatex2.c:2770) ==4016== by 0x80A168B: handle_right_brace (luatex3.c:2431) ==4016== by 0x80A8D28: main_control (luatex3.c:2912) ==4016== by 0x805A796: main_body (luatexini.c:5910) ==4016== by 0x80AE866: main (luatexextra.c:378) (this is from luatex, but I get the same warnings for 1.40.1) It is a bit of a mystery to me what the right way to set up the z_stream is, so I thought I'd first ask if somebody else knows. Best, Taco