mkostemp(), mkostemps()
Make a unique temporary filename and open the file, specifying some flags
Synopsis:
#include <stdlib.h>
#include <fcntl.h>
int mkostemp( char* template,
int oflags );
int mkostemps( char *template,
int slen,
int oflags );
Arguments:
- template
- A template for the filename that you want to use. For mkostemp(), this template can be any file name with at least six X characters appended to it (for example, /tmp/temp.XXXXXX); for mkostemps(), it also includes a suffix (e.g., /tmp/temp.XXXXXXsuffix).
- slen
- (mkostemps() only) The length of the suffix included in the template.
- oflags
- Zero or more of the following flags for the underlying
open():
- O_APPEND — append on each write.
- O_CLOEXEC — set the close-on-exec flag on the new file descriptor.
- O_DSYNC — subsequent I/O waits until all data is successfully transferred to the storage device.
- O_LARGEFILE — allow the file offset to be 64 bits long.
- O_RSYNC — read I/O operations on the file descriptor complete at the same level of integrity as specified by O_DSYNC and O_SYNC.
- O_SYNC — perform synchronous I/O operations.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The mkostemp() and mkostemps() functions take the given file name template and overwrite a portion of it to create a filename.
The generated file name is unique and suitable for use by the application. The Xs are replaced with the current process number and/or a unique letter combination. The number of unique file names that these functions can return depends on the number of Xs provided; the functions try at least 231 combinations before giving up.
The mkostemp() and mkostemps() functions (unlike mktemp()) create the template file, mode 0600 (i.e., read-write for the owner), returning a file descriptor opened for reading and writing. This avoids the race between testing for a file's existence and opening it for use.
Returns:
The file descriptor of the temporary file, or -1 if no suitable file could be created (errno is set).
Errors:
- EINVAL
- One of the following:
- The template doesn't include at least six X wildcard characters, or (for mkostemps()) the length of the template is less than slen.
- The flags argument is invalid.
- EEXIST
- All the names tried already exist. Consider adding more wildcard characters to the template.
This function may also set errno to any value specified by open().
Classification:
| Safety: | |
|---|---|
| Cancellation point | Yes |
| Signal handler | Yes |
| Thread | Yes |