fcntl.h

Purpose

     Defines file control options.

Synopsis

     #include <fcntl.h>

Description

     The fcntl.h  header file defines  the values that  can be
     specified for  the cmd  and arg  parameters of  the fcntl
     system  call, and  for the  oflag parameter  of the  open
     system call.

          /* Flag values accessible to open and fcntl */
          /* The first three can only be set by open */

          #define O_RDONLY  0
          #define O_WRONLY  1
          #define O_RDWR    2
          #define O_NDELAY  04   /* Non-blocking I/O */
          #define O_APPEND  010  /* (0x08) append (writes guaranteed */
                                              /*        at the end) */

          /* Flag values accessible only to open */
          #define O_CREAT 00400  /* (0x0100) open with create (uses third */
                                             /*                open arg) */
          #define O_TRUNC 01000  /* (0x0200) open with truncation */
          #define O_EXCL  02000  /* (0x0400) exclusive open */

          /* fcntl requests */
          #define F_DUPFD 0      /* Duplicate fildes */
          #define F_GETFD 1      /* Get fildes flags */
          #define F_SETFD 2      /* Set fildes flags */
          #define F_GETFL 3      /* Get file flags */
          #define F_SETFL 4      /* Set file flags */
          #define F_GETLK 5      /* Get file lock */
          #define F_SETLK 6      /* Set file lock */
          #define F_SETLKW 7     /* Set file lock and wait */

          /* file segment locking set data type - information passed to */
          /* system by user */

          struct flock {
               short   l_type;
               short   l_whence;
               long    l_start;
               long    l_len;      /* len = 0 means until end of file */
               unsigned long   l_sysid;
               short   l_pid;
          };

          /* file segment locking types */
          #define F_RDLCK 01     /* Read lock */
          #define F_WRLCK 02     /* Write lock */
          #define F_UNLCK 03     /* Remove lock(s) */

File

     /usr/include/fcntl.h

Related Information

     In this book:  "fcntl" and "open."