set_contents_full
Description:
public bool set_contents_full (string filename, string contents, ssize_t length = -1, FileSetContentsFlags flags = 0, int mode = 0666) throws FileError
Writes all of contents
to a file named filename
, with good error checking.
If a file called filename
already exists it will be overwritten.
flags
control the properties of the write operation: whether it’s atomic, and what the tradeoff is between returning quickly or
being resilient to system crashes.
As this function performs file I/O, it is recommended to not call it anywhere where blocking would cause problems, such as in the main loop of
a graphical application. In particular, if flags
has any value other than g_file_set_contents_none
then this function may call `fsync()`.
If g_file_set_contents_consistent is set in flags
, the operation is atomic in the sense that it
is first written to a temporary file which is then renamed to the final name.
Notes:
- On UNIX, if
filename
already exists hard links tofilename
will break. Also since the file is recreated, existing permissions, access control lists, metadata etc. may be lost. Iffilename
is a symbolic link, the link itself will be replaced, not the linked file. - On UNIX, if
filename
already exists and is non-empty, and if the system supports it (via a journalling filesystem or equivalent), and if g_file_set_contents_consistent is set inflags
, the `fsync()` call (or equivalent) will be used to ensure atomic replacement:filename
will contain either its old contents orcontents
, even in the face of system power loss, the disk being unsafely removed, etc. - On UNIX, if
filename
does not already exist or is empty, there is a possibility that system power loss etc. after calling this function will leavefilename
empty or full of NUL bytes, depending on the underlying filesystem, unless g_file_set_contents_durable and g_file_set_contents_consistent are set inflags
. - On Windows renaming a file will not remove an existing file with the new name, so on Windows there is a race condition between the existing file being removed and the temporary file being renamed.
- On Windows there is no way to remove a file that is open to some process, or mapped into memory. Thus, this function will fail if
filename
already exists and is open.
If the call was successful, it returns true. If the call was not successful, it returns false and sets throws. The error domain is g_file_error. Possible error codes are those in the FileError enumeration.
Note that the name for the temporary file is constructed by appending up to 7 characters to filename
.
If the file didn’t exist before and is created, it will be given the permissions from mode
. Otherwise, the permissions of the
existing file may be changed to mode
depending on flags
, or they may remain unchanged.
Parameters:
filename |
name of a file to write |
contents |
string to write to the file |
flags |
flags controlling the safety vs speed of the operation |
mode |
file mode, as passed to `open()`; typically this will be `0666` |
length |
length of |
Returns:
true on success, false if an error occurred |