[fs.conform.os]

# 31 Input/output library [[input.output]](./#input.output)

## 31.12 File systems [[filesystems]](filesystems#fs.conform.os)

### 31.12.2 Conformance [[fs.conformance]](fs.conformance#fs.conform.os)

#### 31.12.2.3 Operating system dependent behavior conformance [fs.conform.os]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L13206)

Behavior that is specified as being[*operating system dependent*](#def:operating_system_dependent "31.12.2.3 Operating system dependent behavior conformance [fs.conform.os]") is dependent upon the behavior
and characteristics of an operating system[.](#1.sentence-1)

The operating system an
implementation is dependent upon isimplementation-defined[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L13215)

It is permissible for an implementation to be dependent upon an operating
system emulator rather than the actual underlying operating system[.](#2.sentence-1)