runtime - what is the GOMAXPROCS default value -

is guaranteed gomaxprocs set 1 when environment variable of same name not set?

this code shows value:

package main  import (     "runtime"     "fmt" )  func getgomaxprocs() int {     return runtime.gomaxprocs(0) }  func main() {     fmt.printf("gomaxprocs %d\n", getgomaxprocs()) } 

and running this:

$ gomaxprocs= go run max.go  gomaxprocs 1 

shows 1 in case, looking confirmation here.

no, there's no guarantee default is; though known implementations use value '1'. if code, in absence of environment variable, requires specific default value should set in code. additionally:

gomaxprocs sets maximum number of cpus can executing simultaneously , returns previous setting. if n < 1, not change current setting. number of logical cpus on local machine can queried numcpu. this call go away when scheduler improves.

(emphasis mine)