cl <- makeCluster(10)
registerDoSNOW(cl)
clusterEvalQ(cl, {
  library(RODBC)
  dbhandle <- odbcDriverConnect(%connectionstring%)
})

[[1]]
[1] -1

[[2]]
RODBC Connection 1
Details:
  case=nochange
  DRIVER=SQL Server
  SERVER=redacted
  UID=
  Trusted_Connection=Yes
  WSID=redacted
  DATABASE=redacted

[[3]]
[1] -1

[[4]]
RODBC Connection 1
Details:
  case=nochange
  DRIVER=SQL Server
  SERVER=redacted
  UID=
  Trusted_Connection=Yes
  WSID=redacted
  DATABASE=redacted