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authorEgor Tensin <Egor.Tensin@gmail.com>2021-03-15 01:14:30 +0300
committerEgor Tensin <Egor.Tensin@gmail.com>2021-03-15 01:22:29 +0300
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tree6ec9411382b221068d6b9009f9d419ab4f6c37a6 /docs/boost.md
parentdocs: markdownify (diff)
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@@ -1,20 +1,23 @@
Library naming
--------------
-The way Boost names library files by default is insane. It's absolutely not compatible between
-OSs, compilers, Boost versions, etc. On Linux, for example, it would create
-stage/lib/libboost_filesystem.a, while on Windows it would become something insane like
-stage\lib\libboost_filesystem-vc142-mt-s-x64-1_72.lib. More than that, older Boost versions
-wouldn't include architecture information (the "x64" part) in the file name, so you couldn't
-store libraries for both x86 and x64 in the same directory. On Linux, on the other hand, you
-can't even store debug/release binaries in the same directory. What's worse is that older CMake
-versions don't support the architecture suffix, choking on the Windows example above.
-
-With all of that in mind, I decided to bring some uniformity by sacrificing some flexibility.
-b2 is called with --layout=system, and libraries are put to stage/\<platform\>/\<configuration\>/lib,
-where \<platform\> is x86/x64 and \<configuration\> is CMake's CMAKE_BUILD_TYPE. That means that I
-can't have libraries with different runtime-link values in the same directory, but I don't really
-care.
+The way Boost names library files by default is insane. It's absolutely not
+compatible between OSs, compilers, Boost versions, etc. On Linux, for example,
+it would create stage/lib/libboost_filesystem.a, while on Windows it would
+become something insane like stage\lib\libboost_filesystem-vc142-mt-s-x64-1_72.lib.
+More than that, older Boost versions wouldn't include architecture information
+(the "x64" part) in the file name, so you couldn't store libraries for both x86
+and x64 in the same directory. On Linux, on the other hand, you can't even
+store debug/release binaries in the same directory. What's worse is that older
+CMake versions don't support the architecture suffix, choking on the Windows
+example above.
+
+With all of that in mind, I decided to bring some uniformity by sacrificing
+some flexibility. b2 is called with `--layout=system`, and libraries are put to
+stage/\<platform\>/\<configuration\>/lib, where \<platform\> is x86/x64 and
+\<configuration\> is CMake's CMAKE_BUILD_TYPE. That means that I can't have
+libraries with different runtime-link values in the same directory, but I don't
+really care.
Hate speech
-----------
@@ -22,27 +25,27 @@ Hate speech
Is there a person who doesn't hate Boost.Build? I'm not sure, I'm definitely
_not_ one of these people. Maybe it's the lack of adoption (meaning that
learning it is useless outside of Boost), maybe it's the incomprehensible
-syntax. Maybe it's the absolutely insane compiler-specific configuration
-files (tools/build/src/tools/*.jam), which are impossible to figure out.
-Maybe it's the fact that the implementation switched from C to C++ while some
-half-baked Python implementation has been there since at least 2015 (see the
-marvelous memo "Status: mostly ported." at the top of tools/build/src/build_system.py).
+syntax. Maybe it's the absolutely insane compiler-specific configuration files
+(tools/build/src/tools/*.jam), which are impossible to figure out. Maybe it's
+the fact that the implementation switched from C to C++ while some half-baked
+Python implementation has been there since at least 2015 (see the marvelous
+memo "Status: mostly ported." at the top of tools/build/src/build_system.py).
What I hate the most though is how its various subtle, implicit and invisible
-decision-making heuristics changed thoughout the release history of Boost.
-You have a config and a compiler that will happily build version 1.65.0?
-Great! Want to use the same config and the same compiler to build version
-1.72.0? Well, too fucking bad, it doesn't work anymore. This I really do
-hate the most.
+decision-making heuristics changed thoughout the release history of Boost. You
+have a config and a compiler that will happily build version 1.65.0? Great!
+Want to use the same config and the same compiler to build version 1.72.0?
+Well, too fucking bad, it doesn't work anymore. This I really do hate the
+most.
Three kinds of toolsets
-----------------------
-b2 accepts the toolset= parameter. What about building b2 itself though?
+b2 accepts the `toolset=` parameter. What about building b2 itself though?
Well, this is what the bootstrap.{sh,bat} scripts do. They also accept a
-toolset argument, but it is _completely_ different to that of b2. That's
-sort of OK, since e.g. cross-compiling b2 is something we rarely want to do
-(and hence there must typically be a native toolset available).
+toolset argument, but it is _completely_ different to that of b2. That's sort
+of OK, since e.g. cross-compiling b2 is something we rarely want to do (and
+hence there must typically be a native toolset available).
bootstrap.sh and bootstrap.bat are completely different (of course!), and
accept different arguments for their toolset parameters.
@@ -51,27 +54,27 @@ Config file insanity
--------------------
Say, we're building Boost on Windows using the GCC from a MinGW-w64
-distribution. We can pass toolset=gcc and all the required flags on the
-command line no problem. What if we want to make a user configuration file
-so that 1) the command line is less polluted, and 2) it can possibly be
-shared? Well, if we put
+distribution. We can pass `toolset=gcc` and all the required flags on the
+command line no problem. What if we want to make a user configuration file so
+that 1) the command line is less polluted, and 2) it can possibly be shared?
+Well, if we put
using gcc : : : <name>value... ;
there, Boost 1.65.0 will happily build everything, while Boost 1.72.0 will
-complain about "duplicate initialization of gcc". This is because when we
-ran `bootstrap.bat gcc` earlier, it wrote `using gcc ;` in project-config.jam.
-And while Boost 1.65.0 detects that toolset=gcc means we're going to use the
-MinGW GCC, and magically turns toolset=gcc to toolset=gcc-mingw, Boost 1.72.0
-does no such thing, and chokes on the "duplicate" GCC declaration.
+complain about "duplicate initialization of gcc". This is because when we ran
+`bootstrap.bat gcc` earlier, it wrote `using gcc ;` in project-config.jam. And
+while Boost 1.65.0 detects that `toolset=gcc` means we're going to use the
+MinGW GCC, and magically turns `toolset=gcc` to `toolset=gcc-mingw`, Boost
+1.72.0 does no such thing, and chokes on the "duplicate" GCC declaration.
We also cannot put
using gcc : custom : : <options> ;
without the executable path, since Boost insists that `g++ -dumpversion` must
-equal to "custom" (which makes total sense, lol). So we have to force it,
-and do provide the path.
+equal to "custom" (which makes total sense, lol). So we have to force it, and
+do provide the path.
Windows & Clang
---------------
@@ -84,19 +87,19 @@ three main ways to install the native Clang toolchain on Windows:
* install it as part of a MSYS2 installation (`pacman -S mingw-w64-x86_64-clang`),
* install as part of a Visual Studio installation.
-Using the latter method, you can switch a project to use the LLVM toolset
-using Visual Studio, but that's stupid. The former two, on the other hand,
-give us the the required clang/clang++/clang-cl executables, so everything
-seems to be fine.
+Using the latter method, you can switch a project to use the LLVM toolset using
+Visual Studio, but that's stupid. The former two, on the other hand, give us
+the the required clang/clang++/clang-cl executables, so everything seems to be
+fine.
Except it's not fine. Let's start with the fact that prior to 1.66.0,
-toolset=clang is completely broken on Windows. It's just an alias for
+`toolset=clang` is completely broken on Windows. It's just an alias for
clang-linux, and it's hardcoded to require the ar & ranlib executables to
create static libraries. Which is fine on Linux, since, and I'm quoting the
source, "ar is always available". But it's not fine on Windows, since
-ar/ranlib are not, in fact, available there by default. Sure, you can
-install some kind of MinGW toolchain, and it might even work, but what the
-hell, honestly?
+ar/ranlib are not, in fact, available there by default. Sure, you can install
+some kind of MinGW toolchain, and it might even work, but what the hell,
+honestly?
Luckily, both the upstream distribution and the MSYS2 mingw-w64-x86_64-llvm
package come with the llvm-ar and llvm-ranlib utilities. So we can put
@@ -108,21 +111,21 @@ and later call
b2 toolset=clang-custom --user-config=path/to/config.jam ...
-But, as I mentioned, prior to 1.66.0, toolset=clang is _hardcoded_ to use ar
-& ranlib, these exact utility names. So either get them as part of some
-MinGW distribution or build Boost using another toolset.
+But, as I mentioned, prior to 1.66.0, `toolset=clang` is _hardcoded_ to use ar
+& ranlib, these exact utility names. So either get them as part of some MinGW
+distribution or build Boost using another toolset.
Now, it's all fine, but building stuff on Windows adds another thing into the
equation: debug runtimes. When you build Boost using MSVC, for example, it
-picks one of the appropriate /MT[d] or /MD[d] flags to build the Boost
-libraries with. Emulating these flags with toolset=clang is complicated and
+picks one of the appropriate `/MT[d]` or `/MD[d]` flags to build the Boost
+libraries with. Emulating these flags with `toolset=clang` is complicated and
inconvenient. Luckily, there's the clang-cl.exe executable, which aims to
provide command line interface compatible with that of cl.exe.
-Boost.Build even supports toolset=clang-win, which should use clang-cl.exe.
-But alas, it's completely broken prior to 1.69.0. It just doesn't work at
-all. So, if you want to build w/ clang-cl.exe, either use Boost 1.69.0 or
-later, or build using another toolset.
+Boost.Build even supports `toolset=clang-win`, which should use clang-cl.exe.
+But alas, it's completely broken prior to 1.69.0. It just doesn't work at all.
+So, if you want to build w/ clang-cl.exe, either use Boost 1.69.0 or later, or
+build using another toolset.
Cygwin & Clang
--------------
@@ -138,8 +141,8 @@ the following error:
^
GCC doesn't emit an error here because /usr/include is in a pre-configured
-"system" include directories list, and the declaration there take precedence,
-I guess? The root of the problem BTW is that sizeof(unsigned long) is
+"system" include directories list, and the declaration there take precedence, I
+guess? The root of the problem BTW is that sizeof(unsigned long) is
* 4 for MSVC and MinGW-born GCCs,
* 8 for Clang (and, strangely, Cygwin GCC; why don't we get runtime