getdtablesize - get descriptor table size
#include <unistd.h>
int getdtablesize(void);
Feature Test Macro Requirements for glibc (see feature_test_macros (7)):
Feature Test Macro Requirements for glibc (see feature_test_macros (7)):
getdtablesize (): _BSD_SOURCE || _XOPEN_SOURCE >= 500
getdtablesize () returns the maximum number of files a process can have open, one more than the largest possible value for a file descriptor.
The current limit on the number of open files per process.
On Linux, getdtablesize () can return any of the errors described for getrlimit (2); see NOTES below.
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.
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. The libc4 and libc5 versions return OPEN_MAX (set to 256 since Linux 0.98.4).
close (2) dup (2) getrlimit (2) open (2)
