Wanted to search for the man pages of the __builtin_popcount function. I typed in $ man __builtin and hit TAB, which turned it into $man ./__builtin/. Why did this happen ?Then, I typed in _popcount and hit return, but couldn't find the man page. How do I then search for the __builtin_* functions ?
Searching __builtin_popcount in man
gcc
You can use the apropos command to search for keywords within the installed man pages:$ apropos builtinbash-builtins (7)    - bash built-in commands, see bash(1)builtins (7)         - bash built-in commands, see bash(1)$ apropos __builtin_popcount__builtin_popcount: nothing appropriate.$ Doesn't look like there is a man page for this GCC extension.  I think you'll have to use the online documentation instead: Built-in Function: int __builtin_popcount (unsigned int x)Returns the number of 1-bits in x.