PC Extra Super CD 1998 January/PCPLUS131.iso/DJGPP/V2/DJLSR201.ZIP/src/libc/dos/compat/d_open.txh

Text File | 1995-10-09 | 1.6 KB | 86 lines

@node _dos_open, dos
@subheading Syntax

@example
#include <fcntl.h>
#include <share.h>
#include <dos.h>

unsigned int _dos_open(const char *filename, unsigned short mode, int *handle);
@end example

@subheading Description

This is a direct connection to the MS-DOS open function call (%ah = 0x3D).
This function opens the given file with the given mode and puts handle of
file into @var{handle} if openning is successful.
Meaning of @var{mode} parameter is the following:

Access mode bits (in FCNTL.H):
@table @code

@item O_RDONLY (_O_RDONLY) 0x00

Open for read only

@item O_WRONLY (_O_WRONLY) 0x01

Open for write only

@item O_RDWR (_O_RDWR) 0x02

Open for read and write

@end table

Sharing mode bits (in SHARE.H):
@table @code

@item SH_COMPAT (_SH_COMPAT) 0x00

Compatibility mode

@item SH_DENYRW (_SH_DENYRW) 0x10

Deny read/write mode

@item SH_DENYWR (_SH_DENYWR) 0x20

Deny write mode

@item SH_DENYRD (_SH_DENYRD) 0x30

Deny read mode

@item SH_DENYNO (_SH_DENYNO) 0x40

Deny none mode

@end table

Inheritance bits (in FCNTL.H):
@table @code

@item O_NOINHERIT (_O_NOINHERIT) 0x80

File is not inherited by child process

@end table

@xref{_dos_creat}. @xref{_dos_creatnew}. @xref{_dos_read}.
@xref{_dos_write}. @xref{_dos_close}

@subheading Return Value

Returns 0 if successful or DOS error code on error (and sets
@var{errno} to EACCES, EINVAL, EMFILE or ENOENT).

@subheading Example

@example
int handle;

if ( !_dos_open("FOO.DAT", O_RDWR, &handle) )
   puts("Wow, file opening was successful !");
@end example