Re: [Discuss-gnuradio] How does 'make check' find its dependencies?

[Michael Dickens]

On Aug 10, 2006, at 3:31 PM, Johnathan Corgan wrote:

> On Thu, August 10, 2006 12:20, Michael Dickens wrote:
>
> > ... so both the "byteswap" and "sched_setscheduler" are killing my
> > configure for the USRP.  When I change these to:
> >
> >         AC_CHECK_FUNCS([getrusage],[],[succeeded=no])
> >         AC_CHECK_HEADERS([byteswap.h])
> >
> > then everything works as I would expect it for my platform.  Not sure
> > if those changes are really required, or maybe just on some
> > platforms? - MLD
>
> The second line, by eliminating the second macro argument  
> [succeeded=no],
> will prevent the component from being disabled even if this check  
> fails,
> so you're just masking the problem.  (Though I don't know why it still
> works.)

Yep, I know.

> Either Matt or Eric wrote the original m4 macro checks.  I need  
> them to
> confirm whether they still need all the function and header checks,  
> and
> whether those need to be different on different platforms.

1) From usrp/host/apps/test_usrp_standard_rx.cc
and
....._tx.cc:

HAVE_SCHED_SETSCHEDULER is used to try to set a real-time scheduler.   
W/o it, "real time" ("-R") has no effect.  THis is the only reference  
in the USRP's code to this function.

OSX does not implement this function for some reason (it does some of  
the others in /usr/include/sched.h).  Ah well, I guess no "real time"  
for us OSX users for now.

I think it would be nice to not fail on this one, but rather to print  
a warning about lacking real-time or whatever.

2) From host/lib/usrp_bytesex.h:34

#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#else
static inline unsigned short int
bswap_16 (unsigned short int x)
{
  return ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8));
}
#endif

so, while this might not be the -best- method, it certainly works.   
THis is the only reference in the USRP's code to this include file.   
I think Apple provides another function which does this, but I can't  
think of it right now.  Likely as not, it does the same thing as this  
code but with a different function name. - MLD