# JSON_NO_IO

```
#define JSON_NO_IO
```

When defined, headers `<cstdio>`, `<ios>`, `<iosfwd>`, `<istream>`, and `<ostream>` are not included and parse functions relying on these headers are excluded. This is relevant for environments where these I/O functions are disallowed for security reasons (e.g., Intel Software Guard Extensions (SGX)).

## Default definition

By default, `JSON_NO_IO` is not defined.

```
#undef JSON_NO_IO
```

## Examples

Example

The code below forces the library not to use the headers `<cstdio>`, `<ios>`, `<iosfwd>`, `<istream>`, and `<ostream>`.

```
#define JSON_NO_IO 1
#include <nlohmann/json.hpp>

...
```

## Version history

- Added in version 3.10.0.