cpython/Include/myselect.h

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Copyright 1991, 1992 by Stichting Mathematisch Centrum, Amsterdam, The
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/* Common definitions for files that use the BSD select system call.
   This is so complicated because every UNIX variant requires that
   you include a different set of headers.  Customizing this one file
   should be easier than patching each of the files using select()... */


/* XXX You may have to include some of these only if not already included */
#include <sys/types.h>
#include <sys/time.h> /* Implies <time.h> everywhere, as far as I know */
#include <sys/param.h>


/* Hacks for various systems that need hand-holding... */

#ifdef _SEQUENT_
#include <sys/select.h>
/* Sequent doesn't seem to define struct timezone anywhere?!?! */
struct timezone {
    int tz_minuteswest;
    int tz_dsttime;
};
#endif

#ifdef _AIX /* I *think* this works */
/* AIX defines fd_set in a separate file.  Sigh... */
#include <sys/select.h>
#endif



/* (Very) old versions of BSD don't define the FD_* set of macros.
   The following will usually do... */

#ifndef	FD_SETSIZE
#define	FD_SETSIZE	256
#endif

#ifndef FD_SET

typedef long	fd_mask;

#define NFDBITS	(sizeof(fd_mask) * NBBY)	/* bits per mask */
#ifndef howmany
#define	howmany(x, y)	(((x)+((y)-1))/(y))
#endif

typedef	struct fd_set {
	fd_mask	fds_bits[howmany(FD_SETSIZE, NFDBITS)];
} fd_set;

#define	FD_SET(n, p)	((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#define	FD_CLR(n, p)	((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
#define	FD_ISSET(n, p)	((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
#define FD_ZERO(p)	memset((char *)(p), '\0', sizeof(*(p)))

#endif /* FD_SET */