Creates a new file.
| #include <sys\types.h> | ||
| #include <sys\stat.h> | ||
| #include <errno.h> | ||
| #include <io.h> | Required only for function declarations |
int _creat( char *filename, int pmode );
| filename | Path name of new file | |
| pmode | Permission setting |
The _creat function either creates a new file or opens and truncates an existing file. If the file specified by filename does not exist, a new file is created with the given permission setting and is opened for writing. If the file already exists and its permission setting allows writing, _creat truncates the file to length 0, destroying the previous contents, and opens it for writing.
The permission setting, pmode, applies to newly created files only. The new file receives the specified permission setting after it is closed for the first time. The integer expression pmode contains one or both of the manifest constants _S_IWRITE and _S_IREAD, defined in SYS\STAT.H. When both of the constants are given, they are joined with the bitwise-OR operator (|). The pmode argument is set to one of the following values:
| Value | Meaning |
| _S_IWRITE | Writing permitted |
| _S_IREAD | Reading permitted |
| _S_IREAD|_S_IWRITE | Reading and writing permitted |
If write permission is not given, the file is read-only. Note that all files are always readable; it is not possible to give write-only permission. Thus, the modes _S_IWRITE and _S_IREAD|_S_IWRITE are equivalent. With DOS versions 3.0 and later, files opened using _creat are always opened in compatibility mode (see _sopen). With DOS32X, the files are always opened with _SH_DENYNO.
The _creat function applies the current file-permission mask to pmode before setting the permissions (see _umask).
Note that the _creat routine is provided primarily for compatibility with previous libraries. A call to _open with _O_CREAT and _O_TRUNC in the oflag argument is equivalent to _creat and is preferable for new code.
If successful, _creat returns a handle for the created file. Otherwise, it returns –1 and sets errno to one of the following constants:
| Value | Meaning |
| EACCES | Path name specifies an existing read-only file or specifies a directory instead of a file |
| EMFILE | No more handles available (too many open files) |
| ENOENT | Path name not found |
Standards:UNIX
16-Bit:DOS, QWIN, WIN, WIN DLL
32-Bit:DOS32X
Use _creat for compatibility with ANSI naming conventions of non-ANSI functions. Use creat and link with OLDNAMES.LIB for UNIX compatibility.
_chmod, _chsize, _close, _dup, _dup2, _open, _sopen, _umask
/* CREAT.C: This program uses _creat to create the file (or truncate the
* existing file) named data and open it for writing.
*/
#include <sys\types.h>
#include <sys\stat.h>
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
void main( void )
{
int fh;
fh = _creat( "data", _S_IREAD | _S_IWRITE );
if( fh == -1 )
perror( "Couldn't create data file" );
else
{
printf( "Created data file.\n" );
_close( fh );
}
}
Created data file.