Julia 1.7: Issue with/after `BLAS.get_num_threads()`

[carstenbauer]

Julia 1.7.2

julia> using LinearAlgebra

julia> using BLISBLAS

julia> BLISBLAS.get_num_threads()
1

julia> BLAS.get_num_threads()
16790712

julia> BLISBLAS.get_num_threads()
-1359210104

Note that using only BLISBLAS.*_num_threads works just fine:

julia> BLISBLAS.set_num_threads(5)

julia> BLISBLAS.get_num_threads()
5

Julia 1.8.5 & Julia 1.10.3

julia> BLISBLAS.get_num_threads()
1

julia> BLAS.get_num_threads()
64

julia> BLISBLAS.get_num_threads()
1

[jd-foster]

For the Julia 1.7.2 case, the fixes for get/set_num_threads() were added recently, see: JuliaLinearAlgebra/BLIS.jl#3 (comment)
but I think the compat bump might mean that it's still using an earlier blis_jll version 0.9? Or there is something happen with LBT in Julia 1.7? Possibly since BLISBLAS adds to OpenBLAS in LBT by default:

julia> BLAS.lbt_get_config()
LinearAlgebra.BLAS.LBTConfig
Libraries:
├ [ILP64] libopenblas64_.dll
└ [ILP64] libblis.dll

there is some "interference effect"?

[ViralBShah]

➜  ~ julia     
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.12.0 (2025-10-07)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org release
|__/                   |

julia> using BLISBLAS

julia> using LinearAlgebra

julia> BLISBLAS.set_num_threads(5)

julia> BLISBLAS.get_num_threads()
5

julia> BLAS.get_num_threads()
5

julia> BLAS.set_num_threads(3)

julia> BLISBLAS.get_num_threads()
3

julia> BLAS.lbt_get_config()
LinearAlgebra.BLAS.LBTConfig
Libraries: 
└ [ILP64] libblis.4.0.0.dylib