getdtablesize.2 (2010 09)

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getdtablesize(2) getdtablesize(2)
NAME
getdtablesize() - get the size of the per-process file descriptor table
SYNOPSIS
#include <unistd.h>
int getdtablesize(void);
DESCRIPTION
The getdtablesize()
function returns the maximum number of file descriptors that can currently be
stored in a process’ file descriptor table. This maximum number is also known as the soft limit for open
files, and can be adjusted up to the hard limit by calling
setrlimit(). The entries in the descriptor
table are numbered with small integers starting at 0 (zero).
The
getdtablesize()
function returns the total number of file descriptors that a process can have
open simultaneously. Each process is limited to a current maximum (soft limit) and a fixed upper bound
(hard limit) of open file descriptors. This limit is at least 32. The system-defined limits are configurable.
See the descriptions of the
maxfiles_lim and maxfiles
kernel parameters in maxfiles_lim (5) and
maxfiles (5), respectively, for information about changing the system-defined, per-process limit on open
file descriptors.
RETURN VALUES
The
getdtablesize() function returns the size of the descriptor table (soft limit), and is always suc-
cessful.
SEE ALSO
close(2), getrlimit(2), open(2), select(2), setrlimit(2), sysconf(2), maxfiles(5), maxfiles_lim(5).
STANDARDS CONFORMANCE
getdtablesize(): XSH4.2, XSH5.0
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1