NAME

getdtablesize − Get the size of the descriptor table

SYNOPSIS

#include <unistd.h>
int getdtablesize(
        void );

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

getdtablesize(): XSH4.2, XSH5.0

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

DESCRIPTION

The getdtablesize() function returns the maximum number of file descriptors in a process’ descriptor table. Each process has a fixed size descriptor table that is guaranteed to have at least 64 slots.  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 fixed number of open file descriptors. This limit is at least 64. The system-defined limit is configurable. If it is greater than 64, the system will allocate more file descriptors for a process up to the defined maximum. See the descriptions of the open_max_hard and open_max_soft attributes in sys_attrs_proc(5) for information about changing the per-process limit on open file descriptors. 

RETURN VALUES

The getdtablesize() function returns the size of the descriptor table, and is always successful. 

SEE ALSO

Functions: close(2), getrlimit(2), open(2), select(2)

Standards: standards(5)