mingw compilation fails on Ubuntu 18.04 (Bionic)

[adamretter]

Compiling RocksDB on Ubuntu 18.04 (Bionic) with mingw fails.

The steps I took:

$ sudo apt-get install mingw-w64
$ sudo update-alternatives --set x86_64-w64-mingw32-g++ /usr/bin/x86_64-w64-mingw32-g++-posix
$ git clone https://github.com/facebook/rocksdb.git
$ cd rocksdb
$ mkdir build && cd build
$ cmake .. -DCMAKE_C_COMPILER=x86_64-w64-mingw32-gcc -DCMAKE_CXX_COMPILER=x86_64-w64-mingw32-g++ -DCMAKE_SYSTEM_NAME=Windows
$ make rocksdb

The error:

[ 29%] Building CXX object CMakeFiles/rocksdb.dir/file/filename.cc.obj
[ 33%] Building CXX object CMakeFiles/rocksdb.dir/file/sst_file_manager_impl.cc.obj
[ 33%] Building CXX object CMakeFiles/rocksdb.dir/logging/auto_roll_logger.cc.obj
[ 33%] Building CXX object CMakeFiles/rocksdb.dir/logging/event_logger.cc.obj
[ 33%] Building CXX object CMakeFiles/rocksdb.dir/logging/log_buffer.cc.obj
/home/aretter/code/rocksdb/logging/log_buffer.cc: In member function ‘void rocksdb::LogBuffer::FlushBufferToLog()’:
/home/aretter/code/rocksdb/logging/log_buffer.cc:63:9: error: ‘localtime_r’ was not declared in this scope
     if (localtime_r(&seconds, &t) != nullptr) {
         ^~~~~~~~~~~
/home/aretter/code/rocksdb/logging/log_buffer.cc:63:9: note: suggested alternative: ‘localtime_s’
     if (localtime_r(&seconds, &t) != nullptr) {
         ^~~~~~~~~~~
         localtime_s
CMakeFiles/rocksdb.dir/build.make:1071: recipe for target 'CMakeFiles/rocksdb.dir/logging/log_buffer.cc.obj' failed
make[3]: *** [CMakeFiles/rocksdb.dir/logging/log_buffer.cc.obj] Error 1
CMakeFiles/Makefile2:3220: recipe for target 'CMakeFiles/rocksdb.dir/all' failed
make[2]: *** [CMakeFiles/rocksdb.dir/all] Error 2
CMakeFiles/Makefile2:3232: recipe for target 'CMakeFiles/rocksdb.dir/rule' failed
make[1]: *** [CMakeFiles/rocksdb.dir/rule] Error 2
Makefile:1156: recipe for target 'rocksdb' failed
make: *** [rocksdb] Error 2

@tamird Any ideas about how to fix this? I tried modifying port/sys_time.h to be like:

#if defined(OS_WIN) && (defined(_MSC_VER) || defined(__MINGW32__))

But that just leads to problems elsewhere in the compilation related to localtime_r.

This is the last issue I need to solve to enable us to update Travis CI to Xenial (#4789)

[tamird]

Xenial has a newer version of mingw-w64 which is more standards compliant. Per the man page of localtime_r:

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
asctime_r(), ctime_r(), gmtime_r(), localtime_r():
_POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _BSD_SOURCE || _SVID_SOURCE || _POSIX_SOURCE

Here's time.h in trusty (v3.1.0): https://github.com/mirror/mingw-w64/blob/v3.1.0/mingw-w64-headers/crt/time.h

Here's time.h in xenial (v5.0.1): https://github.com/mirror/mingw-w64/blob/v5.0.1/mingw-w64-headers/crt/time.h

So I think you need to add #define _POSIX_C_SOURCE 1 here: https://github.com/facebook/rocksdb/blob/master/port/sys_time.h#L42.

[adamretter]

@tamird thanks for the suggestion, unfortunately it doesn't seem to help.

[tamird]

I was able to reproduce. Here's what fixed it:

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 006f679..eda1281 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -183,6 +183,7 @@ else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wsign-compare -Wshadow -Wno-unused-parameter -Wno-unused-variable -Woverloaded-virtual -Wnon-virtual-dtor -Wno-missing-field-initializers -Wno-strict-aliasing")
   if(MINGW)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-format")
+    add_definitions(-D_POSIX_C_SOURCE=1)
   endif()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
   if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")

My guess is that #define in port/sys_time.h is too late. Hope this helps!

[adamretter]

@tamird That fixes the issue. Awesome! - thank you very much :-)