Ocaml 4.02.2 and Lwt 2.5.0 not building on cygwin

[makofka]

tried this with opam and with the tarball. got the same results; 2.4.8 does this as well.

#=== ERROR while installing lwt.2.5.0 =========================================#
# opam-version 1.2.2
# os           cygwin
# command      make build
# path         /home/DMakof0029e/.opam/4.02.2/build/lwt.2.5.0
# compiler     4.02.2
# exit-code    2
# env-file     /home/DMakof0029e/.opam/4.02.2/build/lwt.2.5.0/lwt-3712-58c514.env
# stdout-file  /home/DMakof0029e/.opam/4.02.2/build/lwt.2.5.0/lwt-3712-58c514.out
# stderr-file  /home/DMakof0029e/.opam/4.02.2/build/lwt.2.5.0/lwt-3712-58c514.err
### stdout ###
# [...]
# src/unix/lwt_unix_stubs.c: In function ‘alloc_new_stack’:
# src/unix/lwt_unix_stubs.c:1133:3: warning: implicit declaration of function ‘sigaltstack’ [-Wimplicit-function-declaration]
#    sigaltstack(&new_stack, &old_stack);
#    ^
# src/unix/lwt_unix_stubs.c:1139:21: error: ‘SA_ONSTACK’ undeclared (first use in this function)
#    new_sa.sa_flags = SA_ONSTACK;
#                      ^
# src/unix/lwt_unix_stubs.c:1139:21: note: each undeclared identifier is reported only once for each function it appears in
# Command exited with code 2.
# Makefile:27: recipe for target 'build' failed
### stderr ###
# E: Failure("Command ''/home/DMakof0029e/.opam/4.02.2/bin/ocamlbuild' src/core/lwt.cma src/core/lwt.cmxa src/core/lwt.a src/core/lwt.cmxs src/logger/lwt-log.cma src/logger/lwt-log.cmxa src/logger/lwt-log.a src/logger/lwt-log.cmxs src/unix/liblwt-unix_stubs.a src/unix/dlllwt-unix_stubs.so src/unix/lwt-unix.cma src/unix/lwt-unix.cmxa src/unix/lwt-unix.a src/unix/lwt-unix.cmxs src/simple_top/lwt-simple-top.cma src/simple_top/lwt-simple-top.cmxa src/simple_top/lwt-simple-top.a src/simple_top/lwt-simple-top.cmxs src/react/lwt-react.cma src/react/lwt-react.cmxa src/react/lwt-react.a src/react/lwt-react.cmxs src/preemptive/lwt-preemptive.cma src/preemptive/lwt-preemptive.cmxa src/preemptive/lwt-preemptive.a src/preemptive/lwt-preemptive.cmxs src/ssl/lwt-ssl.cma src/ssl/lwt-ssl.cmxa src/ssl/lwt-ssl.a src/ssl/lwt-ssl.cmxs syntax/lwt-syntax.cma syntax/lwt-syntax.cmxa syntax/lwt-syntax.a syntax/lwt-syntax.cmxs syntax/lwt-syntax-options.cma syntax/lwt-syntax-options.cmxa syntax/lwt-syntax-options.a syntax/lwt-syntax-options.cmxs syntax/lwt-syntax-log.cma syntax/lwt-syntax-log.cmxa syntax/lwt-syntax-log.a syntax/lwt-syntax-log.cmxs ppx/ppx.cma ppx/ppx.cmxa ppx/ppx.a ppx/ppx.cmxs ppx/ppx_lwt_ex.native examples/unix/logging.native examples/unix/relay.native examples/unix/parallelize.native -use-ocamlfind -tag debug' terminated with error code 10")
# make: *** [build] Error 1

[fdopen]

As you can see, cygwin doesn't have sigaltstack yet.
You can try to upgrade to the latest test version of cygwin that provides sigaltstack: https://www.sourceware.org/ml/cygwin-announce/2015-07/msg00032.html

[aantron]

Closing this, as Lwt master (and, I think, Lwt 2.5.2) build with OCaml 4.02.3 on Cygwin now. Please let me know if you need a specific older version to build, and are still having this problem.