sopen

Opens a file or stream for shared access.

Library:LibC
Classification:POSIX
Service:File and Directory I/O

Syntax

  #include <fcntl.h> 
   
  int sopen (
     const char   *path,
     int           oflag,
     int           shflag,
     ...);

Parameters

path

(IN) Points to the path and name of the file to open.

oflag

(IN) Specifies the open access mode. See File Control Open Modes.

shflag

(IN) Specifies the share mode for the file and uses one of the following:

Flag

Value

Description

SH_DENYRW

0x00000010

Deny read and write mode

SH_DENYWR

0x00000020

Deny write mode

SH_DENYRD

0x00000030

Deny read mode

SH_DENYNO

0x00000040

Deny none mode, which allows read and write access to the file
...

(IN) Specifies an optional mode argument when the O_CREAT flag is specified in oflag. See File Access Modes and NetWare Attributes.

Return Values

If successful, returns a file descriptor, which is a non-negative integer. If an error occurs, returns -1 and sets errno to one of the following values:

Decimal

Constant

Description

1

ENONENT

No such file. O_CREAT is not set and the named file does not exist; or O_CREAT is set and either the path prefix does not exist or the path argument points to an empty string.

5

ENOMEM

The system is unable to allocate resources.

6

EACCES

Permission denied.

7

EEXIST

The named file exists and O_CREAT and O_EXCL are set.

9

EINVAL

Invalid parameter.

10

ENFILE

The maximum allowable number of files is currently open in the system.

11

EMFILE

The maximum number of files are currently open.

12

ENOSPC

There is no space left on the device to create the file.

25

ENXIO

The device does not exist.

28

EIO

A physical I/O error occurred.

63

EINTR

A signal was caught during the execution of the function.

64

EISDIR

The specified file is a directory and oflag includes O_WRONLY or O_RDWR.

65

ENAMETOOLONG

The length of the path parameter exceeds the maximum allowed length, or a component of the path parameter is longer than the maximum name length.

67

ENOTDIR

A component specified in the path parameter is not a directory.

76

EROFS

The named file resides on a read-only file system.

81

EOVERFLOW

The operation would overflow.

Remarks

The sopen function returns a file descriptor that refers to the file. The path parameter supplies the name of the file to open. The file is accessed according to the access mode specified by the oflag parameter.

If the O_CREAT flag is set in the oflag parameter, the shflag parameter is ignored and the fourth parameter is a mode parameter of type mode_t. For the flags to use with this parameter, see File Access Modes and NetWare Attributes.

You pass the returned file descriptor to other POSIX functions to perform operations on the file, such as reading and writing.

See Also