# Extra Clang Tools 21.1.8 documentation

## clang-tidy - portability-restrict-system-includes

# portability-restrict-system-includes

Checks to selectively allow or disallow a configurable list of system headers.

For example:

In order to only allow zlib.h from the system you would set the options to -*,zlib.h.

    #include <curses.h>       // Bad: disallowed system header.
    #include <openssl/ssl.h>  // Bad: disallowed system header.
    #include <zlib.h>         // Good: allowed system header.
    #include "src/myfile.h"   // Good: non-system header always allowed.

In order to allow everything except zlib.h from the system you would set the options to *,-zlib.h.

    #include <curses.h>       // Good: allowed system header.
    #include <openssl/ssl.h>  // Good: allowed system header.
    #include <zlib.h>         // Bad: disallowed system header.
    #include "src/myfile.h"   // Good: non-system header always allowed.

Since the options support globbing you can use wildcarding to allow groups of headers.

-*,openssl/*.h will allow all openssl headers but disallow any others.

    #include <curses.h>       // Bad: disallowed system header.
    #include <openssl/ssl.h>  // Good: allowed system header.
    #include <openssl/rsa.h>  // Good: allowed system header.
    #include <zlib.h>         // Bad: disallowed system header.
    #include "src/myfile.h"   // Good: non-system header always allowed.

## Options

Includes

  A string containing a comma separated glob list of allowed include filenames. Similar to the -checks glob list for running clang-tidy itself, the two wildcard characters are * and -, to include and exclude globs, respectively. The default is *, which allows all includes.