02-21-2010
You're not doing low-level I/O here, your write is probably going straight into cache. Try opening with O_DIRECT.
Please edit your post to put code in code tags like the thread posting page suggests. [ code ] stuff [ /code ] without the spaces in the tags. Preferably before a mod needs to do so for you.
Surely you could write custom patterns with either dd or dd_rescue though! dd_rescue in particular shows lots of progress info. Just feed them custom patterns on stdin and you'll have your custom patterns.
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LEARN ABOUT DEBIAN
tcl_access
Tcl_Access(3tcl) Tcl Library Procedures Tcl_Access(3tcl)
__________________________________________________________________________________________________________________________________________________
NAME
Tcl_Access, Tcl_Stat - check file permissions and other attributes
SYNOPSIS
#include <tcl.h>
int
Tcl_Access(path, mode)
int
Tcl_Stat(path, statPtr)
ARGUMENTS
char *path (in) Native name of the file to check the attributes of.
int mode (in) Mask consisting of one or more of R_OK, W_OK, X_OK and F_OK. R_OK, W_OK and X_OK request checking
whether the file exists and has read, write and execute permissions, respectively. F_OK just
requests checking for the existence of the file.
struct stat *statPtr (out) The structure that contains the result.
_________________________________________________________________
DESCRIPTION
As of Tcl 8.4, the object-based APIs Tcl_FSAccess and Tcl_FSStat should be used in preference to Tcl_Access and Tcl_Stat, wherever possi-
ble.
There are two reasons for calling Tcl_Access and Tcl_Stat rather than calling system level functions access and stat directly. First, the
Windows implementation of both functions fixes some bugs in the system level calls. Second, both Tcl_Access and Tcl_Stat (as well as
Tcl_OpenFileChannelProc) hook into a linked list of functions. This allows the possibility to reroute file access to alternative media or
access methods.
Tcl_Access checks whether the process would be allowed to read, write or test for existence of the file (or other file system object) whose
name is pathname. If pathname is a symbolic link on Unix, then permissions of the file referred by this symbolic link are tested.
On success (all requested permissions granted), zero is returned. On error (at least one bit in mode asked for a permission that is
denied, or some other error occurred), -1 is returned.
Tcl_Stat fills the stat structure statPtr with information about the specified file. You do not need any access rights to the file to get
this information but you need search rights to all directories named in the path leading to the file. The stat structure includes info
regarding device, inode (always 0 on Windows), privilege mode, nlink (always 1 on Windows), user id (always 0 on Windows), group id (always
0 on Windows), rdev (same as device on Windows), size, last access time, last modification time, and creation time.
If path exists, Tcl_Stat returns 0 and the stat structure is filled with data. Otherwise, -1 is returned, and no stat info is given.
KEYWORDS
stat, access
Tcl 8.1 Tcl_Access(3tcl)