dgettext fails: index out of bounds,___mo_lookup@

[zekoz]

Here is a minimal repro case, assuming you have vlc installed for the i18n files.

#include <libintl.h>
#include <locale.h>
#include <stdio.h>

int main(int argc, char **argv)
{
  printf("%s\n", setlocale(LC_ALL, "fr"));
  bindtextdomain("vlc", "/usr/share/locale");
  textdomain("vlc");
  printf("%s\n", dgettext("vlc", "ASCII Art"));
}

emcc intl.c -o intl-em.html -g4 --preload-file

/usr/share/locale/fr/LC_MESSAGES/vlc.mo@/usr/share/locale/fr/LC_MESSAGES/vlc.mo
exception thrown: RuntimeError: index out of bounds,___mo_lookup@http://localhost:6931/intl-em.js:9910:1
_dcngettext@http://localhost:6931/intl-em.js:34036:1
_dgettext@http://localhost:6931/intl-em.js:33154:1
_main@http://localhost:6931/intl-em.js:1419:1
Module._main@http://localhost:6931/intl-em.js:5440:10
callMain@http://localhost:6931/intl-em.js:5641:15
doRun@http://localhost:6931/intl-em.js:5699:42
run/<@http://localhost:6931/intl-em.js:5710:7

How do I even debug this? Is there a way for me to build libc with source maps so I can at least step through in the browser debugger?

[zekoz]

Here is where it gets interesting. When I go into the libc and copy the whole function __map_file (and rename) from system/lib/libc/musl/src/time/__map_file.c into .../musl/src/local/dcngettext.c, everything works. Except for a nagging warning: "undefined symbol: memalign".

edit: so __map_file is set to always return -1.

emscripten/src/library.js

Line 2250 in ecb7bb3

__map_file: function(pathname, size) {

[stale]

This issue has been automatically marked as stale because there has been no activity in the past year. It will be closed automatically if no further activity occurs in the next 7 days. Feel free to re-open at any time if this issue is still relevant.

[qsantos]

Same problem, same solution for me. For anyone with similar woes, musl's dcngettext() has some quirks:

• it only checks LC_MESSAGES (so changing LANGUAGE does nothing)
• it uses it naively, so you should set it to e.g. fr, not fr_FR.UTF-8

[qsantos]

Feel free to re-open at any time if this issue is still relevant.

Not possible for unprivileged contributors, it seems.

[stale]

This issue has been automatically marked as stale because there has been no activity in the past year. It will be closed automatically if no further activity occurs in the next 30 days. Feel free to re-open at any time if this issue is still relevant.

[sbc100]

Is this still an issue?

[past-due]

Is this still an issue?

From what I can see, this now works (testing with 3.1.18) - with the important caveat that the FS backend must provide mmap support (of course).

This might be worth documenting somewhere, as it took a bit of digging to realize that passing -s LZ4=1 was causing mmap to fail in my test (and, thus, a complete failure to load message catalogs for gettext) because library_lz4.js does not implement mmap in its stream_ops (yet).