getdtablesize(2)getdtablesize(2)NAMEgetdtablesize() - get the size of the per-process file descriptor table
The 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 The entries in the descriptor
table are numbered with small integers starting at 0 (zero).
The 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 and kernel param‐
eters in maxfiles_lim(5) and maxfiles(5), respectively, for information
about changing the system-defined, per-process limit on open file
The function returns the size of the descriptor table (soft limit), and
is always successful.
SEE ALSOclose(2), getrlimit(2), open(2), select(2), setrlimit(2), sysconf(2),