In Linux, how do I get the man pages for C functions rather than shell commands?
For example, when I type man bind, I get the manual page for the shell command bind and not the man page for socket binding C function.
2 Answers
Use:
man 2 bind
You need a result from a different section of the manual! Man searches various sections for the information you want. As devnull lists, the number indicates which section to search.
Incidentally, bind is a system call, not a C library function. System calls (kernel calls) are in section 2 of the manual, and library functions are in section 3.
man man will tell you how to use the man command!
3 Comments
Emil H
It might be worth clarifying that system calls are in the (2) section, and library functions in the (3) section. I.e.
man 3 printf for printf().
mpr
I've been using Unix for over ten years and wasn't aware of this (always fell back to Internet searches). I would type something like man
sleep\(3\) and give up! I think users would be more likely to reach their desired destination if the man pages read "SEE ALSO man 3 sleep".
Peter Mortensen
There is also a 'bind' in section 3.
Saying man man would tell you:
SYNOPSIS man ... [[section] page ...] ...
The table below shows the section numbers of the manual followed by the types of pages they contain. 1 Executable programs or shell commands 2 System calls (functions provided by the kernel) 3 Library calls (functions within program libraries) 4 Special files (usually found in /dev) 5 File formats and conventions eg /etc/passwd 6 Games 7 Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7) 8 System administration commands (usually only for root) 9 Kernel routines [Non standard]
For example, man 1 printf would show the manual for the printf shell utility, while man 3 printf would show the manual for printf() in libc.
(When in doubt, say man -k foobar. It will provide a list of man pages with foobar as the regex.)
4 Comments
T.Chmelevskij
I've been using man for a bit now, but somehow never tried to do
man man.... Thanks!
Thoth
Interesting. For me,
man 3 printf returns No manual entry for printf in section 3
green marker
After installing 'man-pages', 'man 3 printf' shows correct info.
o11c
man -a is a convenient to get to the page you want, but man -s 3,2,3p is probably best when you know you want C. 3 must be before 2 for things like exit which are different, but 3p must be explicitly after 2 to avoid picking up posix, perl, etc. if you have their man pages installed.
man bind, I get the manual page for the shell commandbindand not the man page for socket binding C function": On what system? What version? What Linux distribution? Or other kind of Unix-like system? I do get the socket binding C function on Ubuntu, "BIND(2)".man -s 1 bindeven returns "No manual entry for bind"