getdtablesize(2) [freebsd man page]

GETDTABLESIZE(2)					      BSD System Calls Manual						  GETDTABLESIZE(2)

NAME

     getdtablesize -- get file descriptor limit

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     getdtablesize(void);

DESCRIPTION

     The getdtablesize() system call returns the maximum number of file descriptors that the current process may open.	The maximum file descrip-
     tor number that the system may assign is the return value minus one.  Existing file descriptor numbers may be higher if the limit was lowered
     after they were opened.

SEE ALSO

     close(2), closefrom(2), dup(2), getrlimit(2), sysconf(2)

HISTORY

     The getdtablesize() system call appeared in 4.2BSD.

BSD
								  April 24, 2013							       BSD

GETDTABLESIZE(3)					     Linux Programmer's Manual						  GETDTABLESIZE(3)

NAME

       getdtablesize - get descriptor table size

SYNOPSIS

       #include <unistd.h>

       int getdtablesize(void);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getdtablesize():
	   Since glibc 2.12:
	       _BSD_SOURCE ||
		   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
	   Before glibc 2.12:
	       _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

DESCRIPTION

       getdtablesize()	returns  the maximum number of files a process can have open, one more than the largest possible value for a file descrip-
       tor.

RETURN VALUE

       The current limit on the number of open files per process.

ERRORS

       On Linux, getdtablesize() can return any of the errors described for getrlimit(2); see NOTES below.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +----------------+---------------+---------+
       |Interface	| Attribute	| Value   |
       +----------------+---------------+---------+
       |getdtablesize() | Thread safety | MT-Safe |
       +----------------+---------------+---------+
CONFORMING TO

       SVr4, 4.4BSD (the getdtablesize() function first appeared in 4.2BSD).  It is not specified in POSIX.1-2001;  portable  applications  should
       employ sysconf(_SC_OPEN_MAX) instead of this call.

NOTES

       getdtablesize()	is  implemented  as  a	libc library function.	The glibc version calls getrlimit(2) and returns the current RLIMIT_NOFILE
       limit, or OPEN_MAX when that fails.

SEE ALSO

       close(2), dup(2), getrlimit(2), open(2)

Linux								    2015-03-02							  GETDTABLESIZE(3)