Fix type of length out parameter #2103

Job	Run time
build on fedora:38 (gcc, false)	1m 51s
build on fedora:38 (clang, false)	2m 21s
build on fedora:37 (gcc, false)	2m 18s
build on fedora:37 (clang, false)	2m 10s
build on centos:7 (gcc, true)	1m 49s
build on ubuntu:23.10 (gcc,false)	1m 22s
build on ubuntu:23.10 (clang,false)	1m 38s
build on ubuntu:23.04 (gcc,false)	1m 17s
build on macos (macos-latest)	1m 16s
build on ubuntu:23.04 (clang,false)	1m 30s
build on macos (macos-latest-xlarge)	46s
build on ubuntu:22.04 (gcc,false)	1m 21s
build on ubuntu:22.04 (clang,true)	1m 49s
build on ubuntu:20.04 (gcc,false)	1m 31s
build on ubuntu:20.04 (clang,false)	1m 25s
build on ubuntu:18.04 (gcc,false)	1m 14s
build on ubuntu:16.04 (gcc,false)	1m 32s
build on ubuntu:14.04 (gcc,false)	1m 15s
build on debian:12 (gcc,false)	1m 22s
build on debian:12 (clang,false)	1m 33s
build on debian:11 (gcc,false)	1m 15s
build on debian:11 (clang,false)	1m 30s
build on debian:10 (gcc,false)	1m 13s
run unit tests (ubuntu:22.04, clang)	10m 43s
run unit tests (centos:7, gcc)	10m 12s
	56m 13s

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