Hi there, I'm building the required portions of Boost myself, along with all my other projects. It turned out that even the smallest compiler setting changes lead to strange crashes, some of which only occured on 5% of the client's systems, so I will not use externally built boost libraries anymore. So now I'm building the parts of boost which I require, which works fine so far. The trouble starts when I tried to use Boost.Context. It also contains ASM code, which I now need to build in Visual Studio 2015. VS2015 does not have builtin Asm support, for x64 it never had. So I'm invoking the Microsoft assembler as a custom build step. Command line is as follows: ml64 /Fo path/to/obj/file.obj /c path/to/source/jump_x86_64_ms_pe_masm.asm Documentation is as scarce as usual, but I figured from the filename that jump_x86_64_ms_pe_masm.asm is the correct file for Microsoft Visual Studio, x64. But assembling failed, and to add insult to injury, the error messages are lost somewhere in the output piping process. The complete output reads like this: ------ 1>------ Erstellen gestartet: Projekt: boost, Konfiguration: Debug x64 ------ 1> Microsoft (R) Macro Assembler (x64) Version 14.00.23506.0 1> Copyright (C) Microsoft Corporation. All rights reserved. 1> 1> Assembling: C:\Projekte\DeadPlanet\SourceExt\boost\context\asm\jump_x86_64_ms_pe_masm.asm 1> C:\Projekte\DeadPlanet\SourceExt\boost\context\asm\jump_x86_64_ms_pe_masm.asm(80)ied size 1>: error A2008 : syntax error : FRAME 1> C:\Projekte\DeadPlanet\SourceExt\boost\context\asm\jump_x86_64_ms_pe_masm.asm(81)ied size 1>CUSTOMBUILD : warning A4020: directive ignored outside a procedure 1> C:\Projekte\DeadPlanet\SourceExt\boost\context\asm\jump_x86_64_ms_pe_masm.asm(215 1>CUSTOMBUILD : fatal error A1010: unmatched block nesting : jump_fcontext ------ Please note that the actual error messages are overwritten by the filename - I can only guess at what buffer magic happens there, but I'm pretty sure it's not intended. But that's just a funny anecdote. My actual question is: how do I build Boost.Context in Visual Studio? Is there maybe some way to see the effective command line when building using Boost.Jam? Is this even the right ASM file for x86_64, Visual Studio? Thanks in advance! Bye, Thomas