value of OPEN_MAX

Question

What is the value of OPEN_MAX on various platforms?

I know that the dynamic limit for the number of open file descriptors can be retrieved through sysconf (_SC_OPEN_MAX), getdtablesize (), or getrlimit (NOFILE, ...). Nonetheless, I want to know how large I can choose file descriptors in the simplest possible case.

When I look at <limits.h> on my system, I only ever get the value for that system.

Answer 1

OPEN_MAX is defined in <limits.h>:

Operating system	Value
AIX ≥ 5.2	65534
AIX < 5.2	32767
macOS	10240
Interix	1024
Linux, Solaris, Cygwin	256
Minix	255
BeOS, Haiku, NetBSD	128
FreeBSD, OpenBSD, OSF/1	64
HP-UX	60
native Windows	32
IRIX	20