reflection - how do you log function call return values in golang -

i want know return values @ time of exit golang function. golang defer mechanism helpful, evaluates arguments @ time defer statement registered rather when executed. can work using anonymous function accesses return values:

func try() (int i) {   defer func() {fmt.printf("%d", i)}()   = 10   return i+1 }  func main() {   try() } 

this work ok, think, handle in generic manner, perhaps like:

func try(in string) (out int) {   enter("%s", in);exit("%d", out) } 

or, better, use reflection output arguments/return values @ time of entry/exit. i'm assuming runtime performance isn't critical :).

is there way this? shaba abhiram's handy tracey lib go long way towards stops short of printing return values.

you correct in assesing arguments deferred function evaluated @ point defer queued, not when executed.

your method of making anonymous function refers named returns valid. approach pass in address of return values:

func try() (i int) {     defer printreturns(time.now(), &i)     time.sleep(10 * time.millisecond)     = 10     return + 1 }  func printreturns(start time.time, rets ...interface{}) {     fmt.println(time.now().sub(start))     _,ret := range rets{         fmt.println(ret)     } } 

the problem approach logging function has pointer instead of real type , must unwrap pointers them. if using reflect, not horribly difficult.