doc: clarify that the “-j N” goes after the “–build build” part #32846

1. 
   bigspider commented at 7:22 am on July 1, 2025: contributor

   I was surprised that something like cmake -j 4 --build build doesn’t work, so this might help others to not make the same mistake.
2. DrahtBot added the label Docs on Jul 1, 2025
3. 
   DrahtBot commented at 7:23 am on July 1, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/32846.

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   Type	Reviewers
   ACK	hebasto, stickies-v, pablomartin4btc, theStack, brunoerg, w0xlt, achow101
   Stale ACK	maflcko

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   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #32269 (doc: update unix build doc with build flags by bufo24)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

4. 
   maflcko commented at 7:30 am on July 1, 2025: member

   lgtm ACK 69f3b2039147558f5c9b452016ab980930e85222
5. 
   hebasto commented at 8:55 am on July 1, 2025: member

   Concept ACK. It follows CMake docs.

   Why not apply such a change across all the docs?

   See the output of git grep -i 'Use "-j N"' for relevant instances.

6. 
   stickies-v commented at 9:06 am on July 1, 2025: contributor

   Concept ACK

   See the output of git grep -i ‘Use “-j N”’ for relevant instances.

   Agreed with this. I also couldn’t find any other patterns that should be updated here.

7. doc: clarify that the "-j N" goes after the "--build build" part

   Also, capitalized the comments in build-unix.md for uniformity
   with the docs on other targets.

   0e9f409db3
8. bigspider force-pushed on Jul 1, 2025
9. 
   bigspider commented at 10:04 am on July 1, 2025: contributor

   Done, and rebased.

   I also noticed that the analogous comments were capitalized in all other build-*.md files, so I capitalized them in build-unix.md as well.

10. hebasto approved
11. 
    hebasto commented at 10:17 am on July 1, 2025: member

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d.
12. DrahtBot requested review from maflcko on Jul 1, 2025
13. DrahtBot requested review from stickies-v on Jul 1, 2025
14. in doc/build-windows.md:50 in 0e9f409db3

    46@@ -47,9 +47,9 @@ This means you cannot use a directory that is located directly on the host Windo
    47 
    48 Build using:
    49 
    50-    gmake -C depends HOST=x86_64-w64-mingw32  # Use "-j N" for N parallel jobs.
    51+    gmake -C depends HOST=x86_64-w64-mingw32  # Append "-j N" for N parallel jobs.
    

    ---

    ---

    

    stickies-v commented at 10:43 am on July 1, 2025:

    review note: gmake seems fine with placing -j earlier, so technically this change isn’t necessary, but it’s probably better to be consistent anyway.

    ---

    

    bigspider commented at 10:48 am on July 1, 2025:

    Good point. Same for ctest, I think.

    ---

    

    stickies-v commented at 11:04 am on July 1, 2025:

    Oh you’re right!
15. stickies-v approved
16. 
    stickies-v commented at 10:44 am on July 1, 2025: contributor

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d
17. in doc/build-unix.md:13 in 0e9f409db3

     8@@ -9,8 +9,8 @@ To Build
     9 
    10 ```bash
    11 cmake -B build
    12-cmake --build build    # use "-j N" for N parallel jobs
    13-cmake --install build  # optional
    14+cmake --build build    # Append "-j N" for N parallel jobs
    15+cmake --install build  # Optional
    

    ---

    ---

    

    purpleKarrot commented at 11:12 am on July 1, 2025:

    cmake --install supports -j too!
18. 
    purpleKarrot commented at 11:23 am on July 1, 2025: contributor

    This may be unrelated, but cmake also respects some environment variables. So instead of passing -j to each command, you could just set CMAKE_BUILD_PARALLEL_LEVEL in bashrc or whatever your favorite shell uses. In fish, I use the following:

     0function cmake
     1  set -x CMAKE_C_COMPILER_LAUNCHER (which ccache)
     2  set -x CMAKE_CXX_COMPILER_LAUNCHER (which ccache)
     3  set -x CMAKE_BUILD_PARALLEL_LEVEL (nproc)
     4  set -x CMAKE_COLOR_DIAGNOSTICS 1
     5  set -x CMAKE_EXPORT_COMPILE_COMMANDS 1
     6  set -x CMAKE_GENERATOR Ninja
     7  set -x CMAKE_INSTALL_PREFIX $HOME/.local
     8  set -x CMAKE_POLICY_VERSION_MINIMUM 3.5
     9  command cmake $argv
    10end
    

19. 
    pablomartin4btc commented at 3:40 pm on July 1, 2025: member

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d
20. theStack approved
21. 
    theStack commented at 4:29 pm on July 1, 2025: contributor

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d

    Makes sense to clarify, have tripped over this as well in the past.

22. brunoerg approved
23. 
    brunoerg commented at 5:11 pm on July 1, 2025: contributor

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d
24. 
    w0xlt commented at 5:18 pm on July 1, 2025: contributor

    ACK https://github.com/bitcoin/bitcoin/pull/32846/commits/0e9f409db3b7b08aef75ce39765b018b69cc8e9d
25. 
    achow101 commented at 6:56 pm on July 1, 2025: member

    ACK 0e9f409db3b7b08aef75ce39765b018b69cc8e9d
26. achow101 merged this on Jul 1, 2025
27. achow101 closed this on Jul 1, 2025

    ---

28. bigspider deleted the branch on Jul 1, 2025
29. fanquake referenced this in commit 83ee49b1dc on Jul 3, 2025
30. 
    fanquake commented at 4:44 pm on July 3, 2025: member

    Backported to 29.x in #32863.

Contributors
bigspider DrahtBot maflcko hebasto stickies-v purpleKarrot pablomartin4btc theStack brunoerg w0xlt achow101 fanquake

Review Requested
maflcko

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