rt/aio.h

   1 /* Copyright (C) 1996-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  * ISO/IEC 9945-1:1996 6.7: Asynchronous Input and Output
  20  */
  21
  22 #ifndef _AIO_H
  23 #define _AIO_H  1
  24
  25 #include <features.h>
  26 #include <sys/types.h>
  27 #include <bits/types/sigevent_t.h>
  28 #include <bits/sigevent-consts.h>
  29 #include <bits/types/struct_timespec.h>
  30
  31 __BEGIN_DECLS
  32
  33 /* Asynchronous I/O control block.  */
  34 struct aiocb
  35 {
  36   int aio_fildes;               /* File descriptor.  */
  37   int aio_lio_opcode;           /* Operation to be performed.  */
  38   int aio_reqprio;              /* Request priority offset.  */
  39   volatile void *aio_buf;       /* Location of buffer.  */
  40   size_t aio_nbytes;            /* Length of transfer.  */
  41   struct sigevent aio_sigevent; /* Signal number and value.  */
  42
  43   /* Internal members.  */
  44   struct aiocb *__next_prio;
  45   int __abs_prio;
  46   int __policy;
  47   int __error_code;
  48   __ssize_t __return_value;
  49
  50 #ifndef __USE_FILE_OFFSET64
  51   __off_t aio_offset;           /* File offset.  */
  52   char __pad[sizeof (__off64_t) - sizeof (__off_t)];
  53 #else
  54   __off64_t aio_offset;         /* File offset.  */
  55 #endif
  56   char __glibc_reserved[32];
  57 };
  58
  59 /* The same for the 64bit offsets.  Please note that the members aio_fildes
  60    to __return_value have to be the same in aiocb and aiocb64.  */
  61 #ifdef __USE_LARGEFILE64
  62 struct aiocb64
  63 {
  64   int aio_fildes;               /* File descriptor.  */
  65   int aio_lio_opcode;           /* Operation to be performed.  */
  66   int aio_reqprio;              /* Request priority offset.  */
  67   volatile void *aio_buf;       /* Location of buffer.  */
  68   size_t aio_nbytes;            /* Length of transfer.  */
  69   struct sigevent aio_sigevent; /* Signal number and value.  */
  70
  71   /* Internal members.  */
  72   struct aiocb *__next_prio;
  73   int __abs_prio;
  74   int __policy;
  75   int __error_code;
  76   __ssize_t __return_value;
  77
  78   __off64_t aio_offset;         /* File offset.  */
  79   char __glibc_reserved[32];
  80 };
  81 #endif
  82
  83
  84 #ifdef __USE_GNU
  85 /* To optimize the implementation one can use the following struct.  */
  86 struct aioinit
  87   {
  88     int aio_threads;            /* Maximum number of threads.  */
  89     int aio_num;                /* Number of expected simultaneous requests.  */
  90     int aio_locks;              /* Not used.  */
  91     int aio_usedba;             /* Not used.  */
  92     int aio_debug;              /* Not used.  */
  93     int aio_numusers;           /* Not used.  */
  94     int aio_idle_time;          /* Number of seconds before idle thread
  95                                    terminates.  */
  96     int aio_reserved;
  97   };
  98 #endif
  99
 100
 101 /* Return values of the aio_cancel function.  */
 102 enum
 103 {
 104   AIO_CANCELED,
 105 #define AIO_CANCELED AIO_CANCELED
 106   AIO_NOTCANCELED,
 107 #define AIO_NOTCANCELED AIO_NOTCANCELED
 108   AIO_ALLDONE
 109 #define AIO_ALLDONE AIO_ALLDONE
 110 };
 111
 112
 113 /* Operation codes for `aio_lio_opcode'.  */
 114 enum
 115 {
 116   LIO_READ,
 117 #define LIO_READ LIO_READ
 118   LIO_WRITE,
 119 #define LIO_WRITE LIO_WRITE
 120   LIO_NOP
 121 #define LIO_NOP LIO_NOP
 122 };
 123
 124
 125 /* Synchronization options for `lio_listio' function.  */
 126 enum
 127 {
 128   LIO_WAIT,
 129 #define LIO_WAIT LIO_WAIT
 130   LIO_NOWAIT
 131 #define LIO_NOWAIT LIO_NOWAIT
 132 };
 133
 134
 135 /* Allow user to specify optimization.  */
 136 #ifdef __USE_GNU
 137 extern void aio_init (const struct aioinit *__init) __THROW __nonnull ((1));
 138 #endif
 139
 140
 141 #ifndef __USE_FILE_OFFSET64
 142 /* Enqueue read request for given number of bytes and the given priority.  */
 143 extern int aio_read (struct aiocb *__aiocbp) __THROW __nonnull ((1));
 144 /* Enqueue write request for given number of bytes and the given priority.  */
 145 extern int aio_write (struct aiocb *__aiocbp) __THROW __nonnull ((1));
 146
 147 /* Initiate list of I/O requests.  */
 148 extern int lio_listio (int __mode,
 149                        struct aiocb *const __list[__restrict_arr],
 150                        int __nent, struct sigevent *__restrict __sig)
 151   __THROW __nonnull ((2));
 152
 153 /* Retrieve error status associated with AIOCBP.  */
 154 extern int aio_error (const struct aiocb *__aiocbp) __THROW __nonnull ((1));
 155 /* Return status associated with AIOCBP.  */
 156 extern __ssize_t aio_return (struct aiocb *__aiocbp) __THROW __nonnull ((1));
 157
 158 /* Try to cancel asynchronous I/O requests outstanding against file
 159    descriptor FILDES.  */
 160 extern int aio_cancel (int __fildes, struct aiocb *__aiocbp) __THROW;
 161
 162 /* Suspend calling thread until at least one of the asynchronous I/O
 163    operations referenced by LIST has completed.
 164
 165    This function is a cancellation point and therefore not marked with
 166    __THROW.  */
 167 extern int aio_suspend (const struct aiocb *const __list[], int __nent,
 168                         const struct timespec *__restrict __timeout)
 169   __nonnull ((1));
 170
 171 /* Force all operations associated with file descriptor described by
 172    `aio_fildes' member of AIOCBP.  */
 173 extern int aio_fsync (int __operation, struct aiocb *__aiocbp)
 174   __THROW __nonnull ((2));
 175 #else
 176 # ifdef __REDIRECT_NTH
 177 extern int __REDIRECT_NTH (aio_read, (struct aiocb *__aiocbp), aio_read64)
 178   __nonnull ((1));
 179 extern int __REDIRECT_NTH (aio_write, (struct aiocb *__aiocbp), aio_write64)
 180   __nonnull ((1));
 181
 182 extern int __REDIRECT_NTH (lio_listio,
 183                            (int __mode,
 184                             struct aiocb *const __list[__restrict_arr],
 185                             int __nent, struct sigevent *__restrict __sig),
 186                            lio_listio64) __nonnull ((2));
 187
 188 extern int __REDIRECT_NTH (aio_error, (const struct aiocb *__aiocbp),
 189                            aio_error64) __nonnull ((1));
 190 extern __ssize_t __REDIRECT_NTH (aio_return, (struct aiocb *__aiocbp),
 191                                  aio_return64) __nonnull ((1));
 192
 193 extern int __REDIRECT_NTH (aio_cancel,
 194                            (int __fildes, struct aiocb *__aiocbp),
 195                            aio_cancel64);
 196 #  ifdef __USE_TIME_BITS64
 197 extern int __REDIRECT_NTH (aio_suspend,
 198                            (const struct aiocb *const __list[], int __nent,
 199                             const struct timespec *__restrict __timeout),
 200                            __aio_suspend_time64) __nonnull ((1));
 201 #  else
 202 extern int __REDIRECT_NTH (aio_suspend,
 203                            (const struct aiocb *const __list[], int __nent,
 204                             const struct timespec *__restrict __timeout),
 205                            aio_suspend64) __nonnull ((1));
 206 #  endif
 207 extern int __REDIRECT_NTH (aio_fsync,
 208                            (int __operation, struct aiocb *__aiocbp),
 209                            aio_fsync64) __nonnull ((2));
 210
 211 # else
 212 #  define aio_read aio_read64
 213 #  define aio_write aio_write64
 214 #  define lio_listio lio_listio64
 215 #  define aio_error aio_error64
 216 #  define aio_return aio_return64
 217 #  define aio_cancel aio_cancel64
 218 #  ifdef __USE_TIME_BITS64
 219 #   define aio_suspend __aio_suspend_time64
 220 #  else
 221 #   define aio_suspend aio_suspend64
 222 #  endif
 223 #  define aio_fsync aio_fsync64
 224 # endif
 225 #endif
 226
 227 #ifdef __USE_LARGEFILE64
 228 extern int aio_read64 (struct aiocb64 *__aiocbp) __THROW __nonnull ((1));
 229 extern int aio_write64 (struct aiocb64 *__aiocbp) __THROW __nonnull ((1));
 230
 231 extern int lio_listio64 (int __mode,
 232                          struct aiocb64 *const __list[__restrict_arr],
 233                          int __nent, struct sigevent *__restrict __sig)
 234   __THROW __nonnull ((2));
 235
 236 extern int aio_error64 (const struct aiocb64 *__aiocbp)
 237   __THROW __nonnull ((1));
 238 extern __ssize_t aio_return64 (struct aiocb64 *__aiocbp)
 239   __THROW __nonnull ((1));
 240
 241 extern int aio_cancel64 (int __fildes, struct aiocb64 *__aiocbp) __THROW;
 242
 243 extern int aio_suspend64 (const struct aiocb64 *const __list[], int __nent,
 244                           const struct timespec *__restrict __timeout)
 245   __THROW __nonnull ((1));
 246
 247 extern int aio_fsync64 (int __operation, struct aiocb64 *__aiocbp)
 248   __THROW __nonnull ((2));
 249 #endif
 250
 251 __END_DECLS
 252
 253 #endif /* aio.h */