liblzma (XZ Utils): lzma/hardware.h File Reference

liblzma (XZ Utils) 5.4.5

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hardware.h File Reference

Hardware information. More...

## Functions
uint64_t | lzma_physmem (void) lzma_nothrow
| Get the total amount of physical memory (RAM) in bytes.
uint32_t | lzma_cputhreads (void) lzma_nothrow
| Get the number of processor cores or threads.

## Detailed Description

Hardware information.

Note
  Never include this file directly. Use <lzma.h> instead.

Since liblzma can consume a lot of system resources, it also provides ways to limit the resource usage. Applications linking against liblzma need to do the actual decisions how much resources to let liblzma to use. To ease making these decisions, liblzma provides functions to find out the relevant capabilities of the underlying hardware. Currently there is only a function to find out the amount of RAM, but in the future there will be also a function to detect how many concurrent threads the system can run.

Note
  On some operating systems, these function may temporarily load a shared library or open file descriptor(s) to find out the requested hardware information. Unless the application assumes that specific file descriptors are not touched by other threads, this should have no effect on thread safety. Possible operations involving file descriptors will restart the syscalls if they return EINTR.

## Function Documentation

## ◆ lzma_physmem()

uint64_t lzma_physmem | ( | void |  | ) |

Get the total amount of physical memory (RAM) in bytes.

This function may be useful when determining a reasonable memory usage limit for decompressing or how much memory it is OK to use for compressing.

Returns
  On success, the total amount of physical memory in bytes is returned. If the amount of RAM cannot be determined, zero is returned. This can happen if an error occurs or if there is no code in liblzma to detect the amount of RAM on the specific operating system.

## ◆ lzma_cputhreads()

uint32_t lzma_cputhreads | ( | void |  | ) |

Get the number of processor cores or threads.

This function may be useful when determining how many threads to use. If the hardware supports more than one thread per CPU core, the number of hardware threads is returned if that information is available.

Returns
  On success, the number of available CPU threads or cores is returned. If this information isn't available or an error occurs, zero is returned.