https://en.cppreference.com/mwiki/index.php?title=Special%3ASearch&search=random&button=
There is only rand in the C search result, while there is random() in man 3 random Linux man page.
As far as I know, 3 in random(3) means it's a library function. Also you can tell this from the manpage:
SYNOPSIS
#include <stdlib.h> //from the standard library
long int random(void);
So why there is no this random function in cppreference?
Why can't I find the random() function in cppreference but can in Linux man page?
why there is no this random function in cppreference?
Because cppreference documents the C standard and not extensions and random() is a linux (BSD, then POSIX) extension to C standard.
Be sure to read future_test_macros(7) and standards(7). Note the random(3) parts:
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
random(), srandom(), initstate(), setstate():
_XOPEN_SOURCE >= 500
|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
and:
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
randomize() and random() are not part of the standard C library. The function random() and srandom() are part of POSIX and not available on Windows. rand() and srand() are part of the standard C library and will be provided by any standard-conforming implementation of C.
This is the cause because you can't find the page of cppreference for random() function. It is a POSIX only function.