sopen

raw OCR

Opens a shared file.

Defined in header <fcntl.h>

Syntax

#include <fcntl.h>
#include <sys\stat.h>
#inGlude <share.h>
#include <io.h>
int sopen(char *path, int access,intshflag[,intmode]);

Portability

DOS	UNIX	Windows	ANSI C	C++ only
■	■	■

Remarks

sopen opens the file given by path and prepares it for shared reading or writing, as determined by access, shflag, and mode.

For sopen, access is constructed by ORing flags bitwise from the following two lists. Only one flag from the first list can be used; the remaining flags can be used in any logical combination.

List 1: Read/write flags

0_RDONLY	Open for reading only.
0_WRONLY	Open for writing only.
0_RDWR	Open for reading and writing.

List 2: Other access flags

0_NDELAY	Not used; for UNIX compatibility.
0_APPEND	If set, the file pointer is set to the end of the file prior to each write.
0_CREAT 0_TRUNC If the file exists, its length is truncated to 0. The file	If the file exists, this flag has no effect. If the file does not exist, the file is created, and the bits of mode are used to set the file attribute bits as in chmod. attributes remain unchanged.
0_EXCL O_BINARY This flag can be given to explicitly open the file in binary	Used only with 0_CREAT. error is returned. mode.	If the file already exists, an
O_TEXT	This flag can be given to explicitly open the file in text mode.

These O_... symbolic constants are defined in fcntl.h.

If neither O_BINARY	nor O_TEXT is given, the file is opened in the

translation mode set by the global variable _fmode.

If the 0_CREAT	flag is used in constructing access, you need to supply the

mode argument to sopen from the following symbolic constants defined in sysXstat.h.

Value of mode	Access permission

S_IWRITE	Permission to write
SJREAD	Permission to read
S IREADIS IWRITE	Permission to read/write

shflag specifies the type of file-sharing allowed on the file pat/z. Symbolic constants for shflag are defined in share.h.

Value of shflag	What it does

SH_COMPAT	Sets compatibility mode
SH_DENYRW	Denies read/write access
SH_DENYWR	Denies write access
SH_DENYRD	Denies read access
SH_DENYNONE	Permits read/write access
SH DENYNO	Permits read/write access

Return value

On successful completion, sopen returns a nonnegative integer (the file handle), and the file pointer (that marks the current position in the file) is set to the beginning of the file. On error, it returns -1, and the global variable errno is set to

ENOENT	Path or file function not found
EMFILE	Too many open files
EACCES	Permission denied
EINVACC	Invalid access code

Example

#include <io.h>
#include <fcntl.h>
#include <sys\stat.h>
#include <process.h>
#include <share.h>
#include <stdio.h>

int main (void)
{
   int handle, status;
   handle = sopen( "c:\\autoexec.bat", 0_RDONLY, SH_DENYNO,  S_IREAD);
   if (handle < 0)  {
      printf ("sopen failed\n");
      exit(l);
   }
   status = access ("c:\\autoexec.bat", 6);
   if (status == 0)
      printf ("read/write access allowed\n");
   else
      printf ("read/write access not allowed\n");
   close (handle);
   return 0;

Differences from modern implementations

Nothing recorded yet.

Modern references

These are search links, not yet checked by hand.

Stable link: /3.1/fcntl.h/sopen/ · short form /3.1/sopen/