fcntl(5)
NAME
fcntl − file control options
SYNOPSIS
#include <fcntl.h>
DESCRIPTION
The <fcntl.h> header defines the following requests and arguments for use by the functions fcntl(2) and open(2).
| Values for cmd used by fcntl (the following values are unique): | ||
| F_DUPFD | Duplicate file descriptor | |
| F_GETFD | Get file descriptor flags | |
| F_SETFD | Set file descriptor flags | |
| F_GETFL | Get file status flags | |
| F_SETFL | Set file status flags | |
| F_GETLK | Get record locking information | |
| F_SETLK | Set record locking information | |
| F_SETLKW | Set record locking information; | |
| wait if blocked | ||
| File descriptor flags used for fcntl: | ||
| FD_CLOEXEC | Close the file descriptor upon | |
| execution of an exec function (see exec(2)) | ||
| Values for l_type used for record locking with fcntl | ||
| (the following values are unique): | ||
| F_RDLCK | Shared or read lock | |
| F_UNLCK | Unlock | |
| F_WRLCK | Exclusive or write lock | |
| The following three sets of values are bitwise distinct: | ||
| Values for oflag used by open | ||
| O_CREAT | Create file if it does not exist | |
| O_EXCL | Exclusive use flag | |
| O_NOCTTY | Do not assign controlling tty | |
| O_TRUNC | Truncate flag | |
| File status flags used for open and fcntl: | ||
| O_APPEND | Set append mode | |
| O_NDELAY | Non-blocking mode | |
| O_NONBLOCK | Non-blocking mode (POSIX) | |
| O_SYNC | Synchronous writes | |
| Mask for use with file access modes: | ||
| O_ACCMODE | Mask for file access modes |
|
| File access modes used for open and fcntl: | ||
| O_RDONLY | Open for reading only | |
| O_RDWR | Open for reading and writing | |
| O_WRONLY | Open for writing only | |
The structure flock describes a file lock. It includes the following members:
shortl_type;/∗ Type of lock ∗/
shortl_whence;/∗ Flag for starting offset ∗/
off_tl_start;/∗ Relative offset in bytes ∗/
off_tl_len;/∗ Size; if 0 then until EOF ∗/
longl_sysid;/∗ Returned with F_GETLK ∗/
pid_tl_pid;/∗ Returned with F_GETLK ∗/
SEE ALSO
creat(2), exec(2), fcntl(2), open(2)
SunOS 5.2 — Last change: 3 Jul 1990