include/sys/select.h

   1 #ifndef _SYS_SELECT_H
   2 #define _SYS_SELECT_H 1
   3
   4 #ifndef _POSIX_SOURCE
   5 #define _POSIX_SOURCE 1
   6 #endif
   7
   8 #include <sys/time.h>
   9 #include <minix/types.h>
  10 #include <limits.h>
  11 #include <string.h>
  12
  13 /* Use this datatype as basic storage unit in fd_set */
  14 typedef u32_t fd_mask;
  15
  16 /* This many bits fit in an fd_set word. */
  17 #define _FDSETBITSPERWORD       (sizeof(fd_mask)*8)
  18
  19 /* Bit manipulation macros */
  20 #define _FD_BITMASK(b)  (1L << ((b) % _FDSETBITSPERWORD))
  21 #define _FD_BITWORD(b)  ((b)/_FDSETBITSPERWORD)
  22
  23 /* Default FD_SETSIZE is OPEN_MAX. */
  24 #ifndef FD_SETSIZE
  25 #define FD_SETSIZE              OPEN_MAX
  26 #endif
  27
  28 /* We want to store FD_SETSIZE bits. */
  29 #define _FDSETWORDS(b)  (((b)+_FDSETBITSPERWORD-1)/_FDSETBITSPERWORD)
  30
  31 typedef struct {
  32         fd_mask fds_bits[_FDSETWORDS(FD_SETSIZE)];
  33 } fd_set;
  34
  35 _PROTOTYPE( int select, (int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *timeout) );
  36
  37 #define FD_ZERO(s) do { int _i; for(_i = 0; _i < _FDSETWORDS(FD_SETSIZE); _i++) { (s)->fds_bits[_i] = 0; } } while(0)
  38 #define FD_SET(f, s) do { (s)->fds_bits[_FD_BITWORD(f)] |= _FD_BITMASK(f); } while(0)
  39 #define FD_CLR(f, s) do { (s)->fds_bits[_FD_BITWORD(f)] &= ~(_FD_BITMASK(f)); } while(0)
  40 #define FD_ISSET(f, s) ((s)->fds_bits[_FD_BITWORD(f)] & _FD_BITMASK(f))
  41
  42 /* possible select() operation types; read, write, errors */
  43 /* (FS/driver internal use only) */
  44 #define SEL_RD          (1 << 0)
  45 #define SEL_WR          (1 << 1)
  46 #define SEL_ERR         (1 << 2)
  47 #define SEL_NOTIFY      (1 << 3) /* not a real select operation */
  48
  49 #endif /* _SYS_SELECT_H */
  50