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; 64