lib/physmem.h

   1 /* Calculate the size of physical memory.
   2
   3    Copyright (C) 2000, 2003, 2009-2024 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #ifndef PHYSMEM_H_
  21 # define PHYSMEM_H_ 1
  22
  23 #ifdef __cplusplus
  24 extern "C" {
  25 #endif
  26
  27
  28 /* Returns the total amount of physical memory.
  29    This value is more or less a hard limit for the working set.  */
  30 double physmem_total (void);
  31
  32 /* Returns the amount of physical memory available.
  33    This value is the amount of memory the application can use without hindering
  34    any other process (assuming that no other process increases its memory
  35    usage).  */
  36 double physmem_available (void);
  37
  38 /* Returns the amount of physical memory that can be claimed, with a given
  39    aggressivity.
  40    For AGGRESSIVITY == 0.0, the result is like physmem_available (): the amount
  41    of memory the application can use without hindering any other process.
  42    For AGGRESSIVITY == 1.0, the result is the amount of memory the application
  43    can use, while causing memory shortage to other processes, but without
  44    bringing the machine into an out-of-memory state.
  45    Values in between, for example AGGRESSIVITY == 0.5, are a reasonable middle
  46    ground.  */
  47 double physmem_claimable (double aggressivity);
  48
  49
  50 #ifdef __cplusplus
  51 }
  52 #endif
  53
  54 #endif /* PHYSMEM_H_ */