fcntl(5)
NAME
fcntl − file control options
SYNOPSIS
#include <sys/types.h>
#include <fcntl.h>
DESCRIPTION
The fcntl(2) function provides for control over open files. This include file describes requests and arguments to fcntl and open(2).
Access modes set by open(2) and accessed by fcntl(2):
O_RDONLY
O_WRONLY
O_RDWR
Mask for file access modes:
O_ACCMODE
File status flags set by open(2) or fcntl(2) and accessed by fcntl(2):
| O_NDELAY | Non-blocking I/O |
| O_NONBLOCK | POSIX-style non-blocking I/O |
| O_APPEND | Append (writes guaranteed at the end) |
| O_SYNCIO | Do write through caching |
Flag values accessible only to open(2):
| O_CREAT | Open with file create (uses third open arg) |
| O_TRUNC | Open with truncation |
| O_EXCL | Exclusive open |
| O_NOCTTY | Do not assign a controlling terminal |
Requests for fcntl(2):
| F_DUPFD | Duplicate fildes |
| F_GETFD | Get file descriptor flags |
| F_SETFD | Set file descriptor flags |
| F_GETFL | Get file flags |
| F_SETFL | Set file flags |
| F_GETLK | Get blocking file lock |
| F_SETLK | Set or clear file locks and fail on busy |
| F_SETLKW | Set or clear file locks and wait on busy |
File descriptor flags for F_GETFD, F_SETFD:
FD_CLOEXEC
File segment locking control structure, struct flock, including the following members:
| short | l_type; | /∗ F_RDLCK, F_WRLCK or F_UNLCK ∗/ | |
| short | l_whence; | /∗ Flag - see lseek(2) ∗/ | |
| off_t | l_start; | /∗ Relative offset in bytes ∗/ | |
| off_t | l_len; | /∗ Size; if 0 then until EOF ∗/ | |
| pid_t | l_pid; | /∗ By F_GETLK - process holding lock ∗/ |
File segment locking types:
| F_RDLCK | Read lock |
| F_WRLCK | Write lock |
| F_UNLCK | Remove locks |
SEE ALSO
STANDARDS CONFORMANCE
<fcntl.h>: AES, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1
Hewlett-Packard Company — HP-UX Release 9.0: August 1992