docs: Windows build intructions result in a large binary #30593

Following the intructions in doc/build-windows.md results in a bitcoind binary that's almost 440 MB. For comparison, the latest release binary is around 15 MB. Are the instructions perhaps missing a flag to create a release build or something like that? I'm using WSL.

It's the debug symbols. If you run strip src/bitcoind.exe you'll end up with a ~15mb binary.

For comparison, the latest release binary is around 15 MB.

The release binaries are stripped of debug info.

Thank you, that was it. It this something worth noting in the docs?

In a post-cmake world this is the type of thing I would expect developers to add to their own cmakuserpresets.json, although I don't see any reason it couldn't be documented too. Compiling without debug symbols is already documented in build-unix.md:

https://github.com/bitcoin/bitcoin/blob/43740f4971f45cd5499470b6a085b3ecd8b96d28/doc/build-unix.md?plain=1#L30

But even building with CFLAGS and CXXFLAGS leaves some info strip is able to remove to further reduce binary size.

Same issue when compiling 27.1 to build my own docker images in alpine. Same process, just switching tags.

 make HOST=$(gcc -dumpmachine) NO_QT=1 NO_ZMQ=1 NO_WALLET=1 NO_BDB=1 NO_SQLITE=1 \
  && ./autogen.sh \
  && ./configure \
    --prefix=$PWD/depends/$(gcc -dumpmachine) LDFLAGS="-static-libstdc++"  \
    --disable-bench \
    --disable-cli \
    --disable-debug \
    --disable-man \
    --disable-tests \
    --disable-upnp \
    --disable-wallet \
    --disable-zmq \
    --with-qrencode=no \
    --enable-fuzz-binary=no \
    --enable-strip \
    --without-gui \
    --without-bdb \
    --with-sqlite=no \    
  && make

REPOSITORY       TAG           IMAGE ID       CREATED         SIZE
bitcoind         27.1          7a14ec692f8c   2 days ago      149MB
bitcoind         26.2          6fc0c7867196   4 days ago      80.1MB

Just adding the option "-s" or "--strip-all". Example: LDFLAGS="-static-libstdc++ -s" reduces the binary in 27.1 to 79 MB.

+1 to adding a note in doc/build-windows.md