manual page distributed with 4.2BSD

SCCS-vsn: lib/libc/sys/open.2 5.1

diff --git a/usr/src/lib/libc/sys/open.2 b/usr/src/lib/libc/sys/open.2
index 4e7ac91..57c17ee 100644 (file)
--- a/usr/src/lib/libc/sys/open.2
+++ b/usr/src/lib/libc/sys/open.2
@@ -2,54 +2,137 @@
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"

-.\"    @(#)open.2      4.1 (Berkeley) %G%
+.\"    @(#)open.2      5.1 (Berkeley) %G%

 .\"
 .\"

-.TH OPEN 2 
+.TH OPEN 2 "2 July 1983"

 .UC 4
 .SH NAME
 .UC 4
 .SH NAME

-open \- open for reading or writing
+open \- open a file for reading or writing, or create a new file

 .SH SYNOPSIS
 .nf
 .SH SYNOPSIS
 .nf

-.B open(name, mode)
-.B char *name;
+.ft B
+#include <sys/file.h>
+.PP
+.ft B
+open(path, flags, mode)
+char *path;
+int flags, mode;

 .fi
 .SH DESCRIPTION
 .I Open
 opens the file
 .fi
 .SH DESCRIPTION
 .I Open
 opens the file

-.I name
-for reading
-(if
-.I mode
-is 0),
-writing (if
+.I path
+for reading and/or writing, as specified by the
+.I flags
+argument and returns a descriptor for that file.
+The
+.I flags
+argument may indicate the file is to be
+created if it does not already exist (by specifying the
+O_CREAT flag), in which case the file is created with mode

 .I mode
 .I mode

-is 1) or for both reading and writing
-(if
-.I mode
-is 2).
-.I Name
+as described in
+.IR chmod (2)
+and modified by the process' umask value (see
+.IR umask (2)).
+.PP
+.I Path

 is the address of a string of ASCII characters representing
 a path name, terminated by a null character.
 is the address of a string of ASCII characters representing
 a path name, terminated by a null character.

+The flags specified are formed by
+.IR or 'ing
+the following values
+.PP
+.RS
+ O_RDONLY      open for reading only
+ O_WRONLY      open for writing only
+ O_RDWR        open for reading and writing
+ O_NDELAY      do not block on open
+ O_APPEND      append on each write
+ O_CREAT       create file if it does not exist
+ O_TRUNC       truncate size to 0
+ O_EXCL        error if create and file exists
+.RE
+.PP
+Opening a file with O_APPEND set causes each write on the file
+to be appended to the end.  If O_TRUNC is specified and the
+file exists, the file is truncated to zero length.
+If O_EXCL is set with O_CREAT, then if the file already
+exists, the open returns an error.  This can be used to
+implement a simple exclusive access locking mechanism.
+If the O_NDELAY flag is specified and the open call would result
+in the process being blocked for some reason (e.g. waiting for
+carrier on a dialup line), the open returns immediately. 
+The first time the process attempts to perform i/o on the open
+file it will block (not currently implemented).
+.PP
+Upon successful completion a non-negative integer termed a
+file descriptor is returned.
+The file pointer used to mark the current position within the
+file is set to the beginning of the file.
+.PP
+The new descriptor is set to remain open across
+.IR execve
+system calls; see
+.IR close (2).

 .PP
 .PP

-The file is positioned at the beginning (byte 0).
-The returned file descriptor must be used for subsequent calls
-for other input-output functions on the file.
+No process may have more than {OPEN_MAX} file descriptors open
+simultaneously.
+.SH "ERRORS
+The named file is opened unless one or more of the
+following are true:
+.TP 15
+[EPERM]
+The pathname contains a character with the high-order bit set.
+.TP 15
+[ENOTDIR]
+A component of the path prefix is not a directory.
+.TP 15
+[ENOENT]
+O_CREAT is not set and the named file does not exist.
+.TP 15
+[EACCES]
+A component of the path prefix denies search permission.
+.TP 15
+[EACCES]
+The required permissions (for reading and/or writing)
+are denied for the named flag.
+.TP 15
+[EISDIR]
+The named file is a directory, and the arguments specify
+it is to be opened for writting.
+.TP 15
+[EROFS]
+The named file resides on a read-only file system,
+and the file is to be modified.
+.TP 15
+[EMFILE]
+{OPEN_MAX} file descriptors are currently open.
+.TP 15
+[ENXIO]
+The named file is a character special or block
+special file, and the device associated with this special file
+does not exist.
+.TP 15
+[ETXTBSY]
+The file is a pure procedure (shared text) file that is being
+executed and the \fIopen\fP call requests write access.
+.TP 15
+[EFAULT]
+.I Path
+points outside the process's allocated address space.
+.TP 15
+[ELOOP]
+Too many symbolic links were encountered in translating the pathname.
+.TP 15
+[EEXIST]
+O_EXCL was specified and the file exists.
+.TP 15
+[ENXIO]
+The O_NDELAY flag is given, and the file is a communications device
+on which their is no carrier present.
+.TP 15
+[EOPNOTSUPP]
+An attempt was made to open a socket (not currently implemented).

 .SH "SEE ALSO"
 .SH "SEE ALSO"

-creat(2), read(2), write(2), dup(2), close(2)
-.SH DIAGNOSTICS
-The value \-1 is returned
-if the file does not exist,
-if one of the necessary directories
-does not exist or is unreadable, if the file is not
-readable (resp. writable), or if too many files are open.
-.SH "ASSEMBLER (PDP-11)"
-(open = 5.)
-.br
-.B sys open; name; mode
-.br
-(file descriptor in r0)
-.SH BUGS
-It should be possible to optionally open files for writing with exclusive use,
-and to optionally call
-.I open
-without the possibility of hanging waiting for carrier on communication lines.
+chmod(2), close(2), dup(2), lseek(2), read(2), write(2), umask(2)