PATH_MAX

Include the <limits.h> or <sys/param.h> header files.

PIPE_BUF

POSIX.1-2001 512 limits.h [1]
POSIX.1-2004 512 limits.h [2]
POSIX.1-2008 512 limits.h [3]
Linux 4,096 linux/limits.h [4]
Mac OS X 512 sys/syslimits.h [5]
FreeBSD 512 sys/syslimits.h [6]
DragonFly BSD 512 sys/syslimits.h [7]
OpenBSD 512 sys/syslimits.h [8]
NetBSD 512 sys/syslimits.h [9]
MINIX 3 32,768 sys/syslimits.h [10]
illumos 5,120 limits.h [11]
QNX Neutrino 5,120 limits.h [12]
OSv 4,096 api/limits.h [13]
Plan 9 8,192 ape/sys/limits.h [14]
[1]http://pubs.opengroup.org/onlinepubs/000095399/basedefs/limits.h.html
[2]http://pubs.opengroup.org/onlinepubs/000095399/basedefs/limits.h.html
[3]http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html
[4]https://github.com/torvalds/linux/blob/master/include/uapi/linux/limits.h#L13
[5]http://src.gnu-darwin.org/src/sys/sys/syslimits.h.html
[6]https://github.com/freebsd/freebsd/blob/master/sys/sys/syslimits.h#L64
[7]http://www.dragonflybsd.org/cvsweb/src/sys/sys/syslimits.h?rev=HEAD
[8]http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/sys/syslimits.h?rev=HEAD&content-type=text/x-cvsweb-markup
[9]http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/sys/syslimits.h?rev=HEAD&content-type=text/x-cvsweb-markup&only_with_tag=MAIN
[10]https://github.com/minix3/minix/blob/master/sys/sys/syslimits.h#L62
[11]https://github.com/illumos/illumos-gate/blob/31c6d826a7f7a4ee7d83c8e99f25d82a4a248076/usr/src/head/limits.h#L91
[12]http://www.qnx.com/developers/docs/660/index.jsp?topic=%2Fcom.qnx.doc.neutrino.utilities%2Ftopic%2Fp%2Fpipe.html
[13]https://github.com/cloudius-systems/osv/blob/master/include/api/limits.h#L42
[14]https://github.com/cao-xx/plan-9/blob/b27a35643e4ee0ede5ed91ecb3a4ed98f8164454/sys/include/ape/sys/limits.h#L24

/dev/{kmem,mem}

References