Board index » cppbuilder » testing for file existence, ios::noreplace does not work

2005-11-17 03:42:20 AM
cppbuilder81
I want to avoid overwriting an existing file so need to test whether a file exists.
I tried:
ofstream outputfile(outfilename,ios::noreplace);
if (!outputfile)
{
cout<<"Error File "<<outfilename<<" already exists";
return 1;
}
This gave me a compiler error:
[C++Error] SAMeas.cpp(119): Undefined symbol 'noreplace'.
What code can I use to check for file existence?
I'm using Borland C++ Builder 3.0
Jeff
 

"Jeff" < XXXX@XXXXX.COM >writes:
feature in pre-standard C++ that was dropped (for better or for
worse.) Even though it's Microsoft documention, this link is useful
for some iostream info: tinyurl.com/8g88h
function (if it's a>2GB file), and only open it if stat() indicates
the file does not already exist. (Well, that simulates the
ios::nocreate feature, but gives the general idea that "you need to
implement it yourself.")
--
Chris (TeamB);
 

On 16 Nov 2005 12:42:20 -0700, Jeff wrote:
and open for write.
--
liz
 

{smallsort}

Tried out stat.
It seems to work.
Thanks!!!!
 

Jeff wrote:
int access(const char *filename, int amode);
if( access( filename, 0 ) != 0 )
Create_and_write_it();
 

Jeff wrote:
inline bool fileExists(const std::string& fname) {
return std::ifstream(fname.c_str()).is_open();
}
//Later in your code
if (!fileExists(myFile)) {
///do what you need to do
}
 

Chris Uzdavinis (TeamB) < XXXX@XXXXX.COM >writes:
creates the file between the points in time when this thread calls
stat() and when it "creates" the file, the file may get overwritten.
I'm afraid something platform specific such as CreateFile() with
CREATE_NEW is needed for a clean solution.
 

Wayne A. King wrote:
like GetFileAttributes, FindFirstFile or c function stat.
Darko
 

Bob Gonder < XXXX@XXXXX.COM >wrote: