Hi,
I'm trying to rectify some scanned maps, but I've this error:
ERROR: error while writing to tmp file
I've checked the write permission of .tmp directory and it's ok...
I've 15 GB of free space.
How can I solve this problem?
The .tmp directory where the .tmp files are saved, are the source
LOCATION (xy) or target LOCATION?
Alfredo
Alfredo:
I'm trying to rectify some scanned maps, but I've
this error:ERROR: error while writing to tmp file
I've checked the write permission of .tmp directory and
it's ok...I've 15 GB of free space.
How can I solve this problem?
The .tmp directory where the .tmp files are saved, are the
source LOCATION (xy) or target LOCATION?
No idea, but the help page says this:
---
If i.rectify starts normally but after some time the following text is seen:
GIS ERROR: error while writing to temp file
the user may try the flag -c (or the module needs more free space on the hard drive).
---
The -c flag: "Use curr. region settings in target location (def.=calculate smallest area)"
the code that triggers that is this, in i.rectify/write.c:
---
offset = ((off_t) row++ * target_window.cols + col) *
G_raster_size(map_type);
lseek(temp_fd,offset,SEEK_SET);
if(write(temp_fd,cell_buf[n],G_raster_size(map_type)*matrix_cols)
!= G_raster_size(map_type)*matrix_cols)
{
unlink(temp_name);
G_fatal_error("error while writing to temp file");
}
---
?does the (off_t) cast only affect nearest row++ and not the whole (row*col+col)? or does the whole thing get promoted once one part of the calc is cast to off_t? or is that ok?
how does the region in your target mapset look like? of your source image?
Hamish
Hamish wrote:
> I'm trying to rectify some scanned maps, but I've
> this error:
>
> ERROR: error while writing to tmp file
>
> I've checked the write permission of .tmp directory and
> it's ok...
>
> I've 15 GB of free space.
>
> How can I solve this problem?
>
> The .tmp directory where the .tmp files are saved, are the
> source LOCATION (xy) or target LOCATION?No idea, but the help page says this:
---
If i.rectify starts normally but after some time the following text is seen:
GIS ERROR: error while writing to temp file
the user may try the flag -c (or the module needs more free space on the hard drive).
---The -c flag: "Use curr. region settings in target location (def.=calculate smallest area)"
the code that triggers that is this, in i.rectify/write.c:
---
offset = ((off_t) row++ * target_window.cols + col) *
G_raster_size(map_type);
lseek(temp_fd,offset,SEEK_SET);if(write(temp_fd,cell_buf[n],G_raster_size(map_type)*matrix_cols)
!= G_raster_size(map_type)*matrix_cols)
{
unlink(temp_name);
G_fatal_error("error while writing to temp file");
}
---
However: note that nothing prior to the above checks that the temp_fd
returned from creat() is valid. So, if creat() fails, the first
indication will be that write() fails (with EBADF).
I suggest adding an explicit check for the return value from creat(),
i.e.:
temp_fd = creat(temp_name,0660);
+ if (temp_fd < 0)
+ G_fatal_error("unable to open temporary file");
This will make it possible to distinguish between an error when
opening the file (e.g. EPERM = "permission denied") and an error when
writing to the file (e.g. ENOSPC = "no space left on device").
?does the (off_t) cast only affect nearest row++ and not the whole
(row*col+col)? or does the whole thing get promoted once one part of
the calc is cast to off_t? or is that ok?
In C, types propagate upwards from the leaves. The result type of a
diadic operator (addition, multiplication) etc is equal to the
"largest" operand type, where long long > long > int, and double is
deemed larger than all integral types.
When dealing with off_t, the general rule is to cast one "limb" of any
multiplication to off_t (it's invariably multiplications where any
truncation will occur). The result of the multiplication will then be
off_t, as will the result of any enclosing expression involving that
value.
So, in the above code, the off_t propagates up to the result of the
first multiplication, and then to the addition, then to the second
multiplication, and then to the assignment.
OTOH, this won't work:
offset = (off_t) ((row++ * target_window.cols + col) * G_raster_size(map_type));
as all of the calculations will be truncated to lesser types (int,
long, size_t), and by the time that the value is cast to off_t
(immediately before the assignment), it has already been truncated.
--
Glynn Clements <glynn@gclements.plus.com>
2008/6/13 Glynn Clements <glynn@gclements.plus.com>:
Hamish wrote:
> I'm trying to rectify some scanned maps, but I've
> this error:
>
> ERROR: error while writing to tmp file
>
> I've checked the write permission of .tmp directory and
> it's ok...
>
> I've 15 GB of free space.
>
> How can I solve this problem?
>
> The .tmp directory where the .tmp files are saved, are the
> source LOCATION (xy) or target LOCATION?No idea, but the help page says this:
---
If i.rectify starts normally but after some time the following text is seen:
GIS ERROR: error while writing to temp file
the user may try the flag -c (or the module needs more free space on the hard drive).
---The -c flag: "Use curr. region settings in target location (def.=calculate smallest area)"
the code that triggers that is this, in i.rectify/write.c:
---
offset = ((off_t) row++ * target_window.cols + col) *
G_raster_size(map_type);
lseek(temp_fd,offset,SEEK_SET);if(write(temp_fd,cell_buf[n],G_raster_size(map_type)*matrix_cols)
!= G_raster_size(map_type)*matrix_cols)
{
unlink(temp_name);
G_fatal_error("error while writing to temp file");
}
---However: note that nothing prior to the above checks that the temp_fd
returned from creat() is valid. So, if creat() fails, the first
indication will be that write() fails (with EBADF).I suggest adding an explicit check for the return value from creat(),
i.e.:temp_fd = creat(temp_name,0660);
+ if (temp_fd < 0)
+ G_fatal_error("unable to open temporary file");This will make it possible to distinguish between an error when
opening the file (e.g. EPERM = "permission denied") and an error when
writing to the file (e.g. ENOSPC = "no space left on device").?does the (off_t) cast only affect nearest row++ and not the whole
(row*col+col)? or does the whole thing get promoted once one part of
the calc is cast to off_t? or is that ok?In C, types propagate upwards from the leaves. The result type of a
diadic operator (addition, multiplication) etc is equal to the
"largest" operand type, where long long > long > int, and double is
deemed larger than all integral types.When dealing with off_t, the general rule is to cast one "limb" of any
multiplication to off_t (it's invariably multiplications where any
truncation will occur). The result of the multiplication will then be
off_t, as will the result of any enclosing expression involving that
value.So, in the above code, the off_t propagates up to the result of the
first multiplication, and then to the addition, then to the second
multiplication, and then to the assignment.OTOH, this won't work:
offset = (off_t) ((row++ * target_window.cols + col) * G_raster_size(map_type));
as all of the calculations will be truncated to lesser types (int,
long, size_t), and by the time that the value is cast to off_t
(immediately before the assignment), it has already been truncated.--
Glynn Clements <glynn@gclements.plus.com>
I've solved....
The region that I've setting is too large 
Now, it's work well...
Alfredo