Closed
Description
Base,gensym() should always return a unique result.
I got currious as to if it did, when having multiple threads.
Answer: Mostly.
MVE:
julia> function tt2()
ret = Vector{Symbol}(10)
Base.Threads.@threads for ii in 1:10
ret[ii] = Base.gensym()
end
ret
end
tt2 (generic function with 1 method)
julia> tt2()
10-element Array{Symbol,1}:
Symbol("##271")
Symbol("##273")
Symbol("##275")
Symbol("##271")
Symbol("##273")
Symbol("##271")
Symbol("##276")
Symbol("##278")
Symbol("##273")
Symbol("##277")
We can see that ##271 and #273 occurs multiple times.
- If I call
tt2()a second time, it seems to always be unique. - If I declare a new method
tt3()is seems like it can occur on the first use of that
I guess this is some play with codegen.
Easy solution would be to append the generating threadid() whenever a symbol is generated.
But this might be a symptom of a deeper issue, so.
This is with:
julia> Base.Threads.nthreads()
10
julia> versioninfo()
Julia Version 0.5.0-rc0+150
Commit 389dc1c (2016-08-03 04:22 UTC)
Platform Info:
System: Linux (x86_64-linux-gnu)
CPU: AMD Opteron 63xx class CPU
WORD_SIZE: 64
BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Piledriver)
LAPACK: libopenblas64_
LIBM: libopenlibm
LLVM: libLLVM-3.7.1 (ORCJIT, bdver2)