1 /** 2 * \file lzma/hardware.h 3 * \brief Hardware information 4 * 5 * Since liblzma can consume a lot of system resources, it also provides 6 * ways to limit the resource usage. Applications linking against liblzma 7 * need to do the actual decisions how much resources to let liblzma to use. 8 * To ease making these decisions, liblzma provides functions to find out 9 * the relevant capabilities of the underlaying hardware. Currently there 10 * is only a function to find out the amount of RAM, but in the future there 11 * will be also a function to detect how many concurrent threads the system 12 * can run. 13 * 14 * \note On some operating systems, these function may temporarily 15 * load a shared library or open file descriptor(s) to find out 16 * the requested hardware information. Unless the application 17 * assumes that specific file descriptors are not touched by 18 * other threads, this should have no effect on thread safety. 19 * Possible operations involving file descriptors will restart 20 * the syscalls if they return EINTR. 21 */ 22 23 /* 24 * Author: Lasse Collin 25 * 26 * This file has been put into the public domain. 27 * You can do whatever you want with this file. 28 * 29 * See ../lzma.h for information about liblzma as a whole. 30 */ 31 32 #ifndef LZMA_H_INTERNAL 33 # error Never include this file directly. Use <lzma.h> instead. 34 #endif 35 36 37 /** 38 * \brief Get the total amount of physical memory (RAM) in bytes 39 * 40 * This function may be useful when determining a reasonable memory 41 * usage limit for decompressing or how much memory it is OK to use 42 * for compressing. 43 * 44 * \return On success, the total amount of physical memory in bytes 45 * is returned. If the amount of RAM cannot be determined, 46 * zero is returned. This can happen if an error occurs 47 * or if there is no code in liblzma to detect the amount 48 * of RAM on the specific operating system. 49 */ 50 extern LZMA_API(uint64_t) lzma_physmem(void) lzma_nothrow; 51 52 53 /** 54 * \brief Get the number of processor cores or threads 55 * 56 * This function may be useful when determining how many threads to use. 57 * If the hardware supports more than one thread per CPU core, the number 58 * of hardware threads is returned if that information is available. 59 * 60 * \brief On success, the number of available CPU threads or cores is 61 * returned. If this information isn't available or an error 62 * occurs, zero is returned. 63 */ 64 extern LZMA_API(uint32_t) lzma_cputhreads(void) lzma_nothrow; 65