1/* SPDX-License-Identifier: 0BSD */
2
3/**
4 * \file lzma/hardware.h
5 * \brief Hardware information
6 * \note Never include this file directly. Use <lzma.h> instead.
7 *
8 * Since liblzma can consume a lot of system resources, it also provides
9 * ways to limit the resource usage. Applications linking against liblzma
10 * need to do the actual decisions how much resources to let liblzma to use.
11 * To ease making these decisions, liblzma provides functions to find out
12 * the relevant capabilities of the underlying hardware. Currently there
13 * is only a function to find out the amount of RAM, but in the future there
14 * will be also a function to detect how many concurrent threads the system
15 * can run.
16 *
17 * \note On some operating systems, these function may temporarily
18 * load a shared library or open file descriptor(s) to find out
19 * the requested hardware information. Unless the application
20 * assumes that specific file descriptors are not touched by
21 * other threads, this should have no effect on thread safety.
22 * Possible operations involving file descriptors will restart
23 * the syscalls if they return EINTR.
24 */
25
26/*
27 * Author: Lasse Collin
28 */
29
30#ifndef LZMA_H_INTERNAL
31# error Never include this file directly. Use <lzma.h> instead.
32#endif
33
34
35/**
36 * \brief Get the total amount of physical memory (RAM) in bytes
37 *
38 * This function may be useful when determining a reasonable memory
39 * usage limit for decompressing or how much memory it is OK to use
40 * for compressing.
41 *
42 * \return On success, the total amount of physical memory in bytes
43 * is returned. If the amount of RAM cannot be determined,
44 * zero is returned. This can happen if an error occurs
45 * or if there is no code in liblzma to detect the amount
46 * of RAM on the specific operating system.
47 */
48extern LZMA_API(uint64_t) lzma_physmem(void) lzma_nothrow;
49
50
51/**
52 * \brief Get the number of processor cores or threads
53 *
54 * This function may be useful when determining how many threads to use.
55 * If the hardware supports more than one thread per CPU core, the number
56 * of hardware threads is returned if that information is available.
57 *
58 * \return On success, the number of available CPU threads or cores is
59 * returned. If this information isn't available or an error
60 * occurs, zero is returned.
61 */
62extern LZMA_API(uint32_t) lzma_cputhreads(void) lzma_nothrow;
63