1  /**
       2   * \file        lzma/hardware.h
       3   * \brief       Hardware information
       4   * \note        Never include this file directly. Use <lzma.h> instead.
       5   *
       6   * Since liblzma can consume a lot of system resources, it also provides
       7   * ways to limit the resource usage. Applications linking against liblzma
       8   * need to do the actual decisions how much resources to let liblzma to use.
       9   * To ease making these decisions, liblzma provides functions to find out
      10   * the relevant capabilities of the underlying hardware. Currently there
      11   * is only a function to find out the amount of RAM, but in the future there
      12   * will be also a function to detect how many concurrent threads the system
      13   * can run.
      14   *
      15   * \note        On some operating systems, these function may temporarily
      16   *              load a shared library or open file descriptor(s) to find out
      17   *              the requested hardware information. Unless the application
      18   *              assumes that specific file descriptors are not touched by
      19   *              other threads, this should have no effect on thread safety.
      20   *              Possible operations involving file descriptors will restart
      21   *              the syscalls if they return EINTR.
      22   */
      23  
      24  /*
      25   * Author: Lasse Collin
      26   *
      27   * This file has been put into the public domain.
      28   * You can do whatever you want with this file.
      29   */
      30  
      31  #ifndef LZMA_H_INTERNAL
      32  #	error Never include this file directly. Use <lzma.h> instead.
      33  #endif
      34  
      35  
      36  /**
      37   * \brief       Get the total amount of physical memory (RAM) in bytes
      38   *
      39   * This function may be useful when determining a reasonable memory
      40   * usage limit for decompressing or how much memory it is OK to use
      41   * for compressing.
      42   *
      43   * \return      On success, the total amount of physical memory in bytes
      44   *              is returned. If the amount of RAM cannot be determined,
      45   *              zero is returned. This can happen if an error occurs
      46   *              or if there is no code in liblzma to detect the amount
      47   *              of RAM on the specific operating system.
      48   */
      49  extern LZMA_API(uint64_t) lzma_physmem(void) lzma_nothrow;
      50  
      51  
      52  /**
      53   * \brief       Get the number of processor cores or threads
      54   *
      55   * This function may be useful when determining how many threads to use.
      56   * If the hardware supports more than one thread per CPU core, the number
      57   * of hardware threads is returned if that information is available.
      58   *
      59   * \return      On success, the number of available CPU threads or cores is
      60   *              returned. If this information isn't available or an error
      61   *              occurs, zero is returned.
      62   */
      63  extern LZMA_API(uint32_t) lzma_cputhreads(void) lzma_nothrow;