Reading a file that is already open by another process

[trellow]

Hello,

I am writing an application that needs to read a file that is already open by another process for writing.

When I do the following:

FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);

I get the following exception:
{"The process cannot access the file \"EV1_0.log\" because it is being used by another process." }

I wrote a test program in "regular" C as follows and do not get this error. It can always read this file.

if ((fp = fopen("EV1_0.log", "r")) == NULL)
{
printf("Failed to open file");
return;
}

if (fgets (result,200, fp) == NULL)
{
printf("Could not read from file");
return;
}

printf(result);

The process that has the file open for writing is written in C and cannot be modified.

Does anyone know how I can access this file for reading using C#? I tried using FileShare.Read as one of the FileStream constructor values and that does not seem to help.

Thanks,
Trellow

[Morten Wennevik]

Try specifying System.IO.FileShare.ReadWrite

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[Philip Rieck]

trellow, try using this line to open your filestream:

FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read,
System.IO.FileShare.ReadWrite)

This overload of the FileStream constructor allows you to open the file in a
non-exclusive mode.

"trellow" <an*******@discussions.microsoft.com> wrote in message
news:6C**********************************@microsof t.com...

Hello,

I am writing an application that needs to read a file that is already open by another process for writing.
When I do the following:

FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);

I get the following exception:
{"The process cannot access the file \"EV1_0.log\" because it is being used by another process." }
I wrote a test program in "regular" C as follows and do not get this error. It can always read this file.
if ((fp = fopen("EV1_0.log", "r")) == NULL)
{
printf("Failed to open file");
return;
}

if (fgets (result,200, fp) == NULL)
{
printf("Could not read from file");
return;
}

printf(result);

The process that has the file open for writing is written in C and cannot be modified.
Does anyone know how I can access this file for reading using C#? I tried using FileShare.Read as one of the FileStream constructor values and that
does not seem to help.
Thanks,
Trellow

[Arild Bakken]

If the other process has specified that the file should not be shared, then
I think you're out of luck, but try with the FileShare.ReadWrite when
opening.

Arild

"trellow" <an*******@discussions.microsoft.com> wrote in message
news:6C**********************************@microsof t.com...

Hello,

I am writing an application that needs to read a file that is already open by another process for writing.
When I do the following:

FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);

I get the following exception:
{"The process cannot access the file \"EV1_0.log\" because it is being used by another process." }
I wrote a test program in "regular" C as follows and do not get this error. It can always read this file.
if ((fp = fopen("EV1_0.log", "r")) == NULL)
{
printf("Failed to open file");
return;
}

if (fgets (result,200, fp) == NULL)
{
printf("Could not read from file");
return;
}

printf(result);

The process that has the file open for writing is written in C and cannot be modified.
Does anyone know how I can access this file for reading using C#? I tried using FileShare.Read as one of the FileStream constructor values and that
does not seem to help.
Thanks,
Trellow