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Re: Support for ITIMER_PROF?

On 6/22/2015 9:25 AM, Corinna Vinschen wrote:
On Jun 22 08:05, Ken Brown wrote:
According to the Cygwin API documentation
(, "getitimer and setitimer
only support ITIMER_REAL for now."  I'm wondering whether there's any chance
that support for ITIMER_PROF might be added.  I have no idea what the
obstacles are.

My reason for asking is that emacs has a CPU profiling function, which
doesn't work on Cygwin because it relies on ITIMER_PROF.  (There's an
alternative implementation, but it requires timer_getoverrun, also not
available in Cygwin.)

Both very tricky.  Given the description of timer_getoverrun and how
this stuff is implemented in Cygwin, you might get away with

   #ifdef __CYGWIN__
   #define timer_getoverrun(x)	0

indepedently of using SIGEV_SIGNAL or SIGEV_THREAD.

This seems to work.  Thanks!

One question: It seems that SIGEV_SIGNAL and friends are defined as macros on Linux (or at least on the one Linux distribution I looked at), but on Cygwin they're only enum constants. And emacs expects them to be defined as macros. Would something like the following be reasonable for the sake of compatibility?

--- a/winsup/cygwin/include/cygwin/signal.h
+++ b/winsup/cygwin/include/cygwin/signal.h
@@ -311,6 +311,10 @@ enum
                                           perform notification */

 #if __WORDSIZE == 64
 typedef __uint64_t sigset_t;


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