[Emscripten][Ubuntu 22.04.3 LTS] Use of undeclared identifier 'SYS_write'

[prantoran]

Hi everyone!

I am building glog with the latest release of emsdk for Bazel and I got the error that SYS_write is not defined. I searched previous issues. I think a similar occurred for OSX but not sure how related it is with my issue.

Here is the exact error from my terminal:

INFO: Found 1 target...
ERROR: /root/.cache/bazel/_bazel_root/1160c8434d4e1dfd4c379a5050d02ad4/external/com_github_glog_glog/BUILD:5:13: Compiling src/raw_logging.cc failed: (Exit 1): emcc.sh failed: error executing command (from target @com_github_glog_glog//:glog) external/emsdk/emscripten_toolchain/emcc.sh '--sysroot=external/emscripten_bin_linux/emscripten/cache/sysroot' -fdiagnostics-color -fno-exceptions -fno-strict-aliasing -funsigned-char ... (remaining 59 arguments skipped)
external/com_github_glog_glog/src/raw_logging.cc:139:3: error: use of undeclared identifier 'SYS_write'
  139 |   safe_write(STDERR_FILENO, buffer, strlen(buffer));
      |   ^
external/com_github_glog_glog/src/raw_logging.cc:63:42: note: expanded from macro 'safe_write'
   63 | # define safe_write(fd, s, len)  syscall(SYS_write, fd, s, len)
      |                                          ^
1 error generated.

The following is the glog setup in WORKSPACE. I used version 0.6.0.

# 23-12-30: copied from https://github.com/google/glog/#building-from-source
http_archive(
    name = "com_github_gflags_gflags",
    sha256 = "34af2f15cf7367513b352bdcd2493ab14ce43692d2dcd9dfc499492966c64dcf",
    strip_prefix = "gflags-2.2.2",
    urls = ["https://github.com/gflags/gflags/archive/v2.2.2.tar.gz"],
)
http_archive(
    name = "com_github_google_glog",
    sha256 = "122fb6b712808ef43fbf80f75c52a21c9760683dae470154f02bddfc61135022",
    strip_prefix = "glog-0.6.0",
    urls = ["https://github.com/google/glog/archive/v0.6.0.zip"],
)

And the following is the emsdk setup in WORKSPACE. I used the version 3.1.51.

# 23-12-12 copied from https://github.com/emscripten-core/emsdk/blob/main/bazel/README.md
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
http_archive(
    name = "emsdk",
    sha256 = "6b206e135ccc3b0d6c02e948eb4b8b95521593b5b4d9788795269bbf6640fcb2",
    strip_prefix = "emsdk-4e2496141eda15040c44e9bbf237a1326368e34c/bazel",
    url = "https://github.com/emscripten-core/emsdk/archive/4e2496141eda15040c44e9bbf237a1326368e34c.tar.gz",
)

load("@emsdk//:deps.bzl", emsdk_deps = "deps")
emsdk_deps()

load("@emsdk//:emscripten_deps.bzl", emsdk_emscripten_deps = "emscripten_deps")
emsdk_emscripten_deps(emscripten_version = "3.1.51")

load("@emsdk//:toolchains.bzl", "register_emscripten_toolchains")
register_emscripten_toolchains()

[sergiud]

Proper Emscripten support was added in #846 shortly after the 0.6.0 release. However, glog is continuously built with Emscripten using CMake only. I believe none of the other maintainers use Bazel for this purpose. Such builds can therefore break anytime.

I therefore suggest testing glog at head first. If that does not work, please submit a PR with a corresponding fix.

[prantoran]

Cool thanks for the context! I will try out and create a PR if applicable.

[sergiud]

Great! I'll close this issue then. If you encounter specific problems at head, just create a new issue.