std::fstream doesn't create file
22,647
Solution 1
You're specifying std::fstream::in
in your call to fstream::open(). This is known to force it to require an existing file.
Either remove std::fstream::in
from your mode
argument, or specify std::fstream::trunc
in addition to the other flags.
Solution 2
It's a little messy but works. Doesn't overwrite the file if it exists but creates a new one if the first open fails.
std::fstream my_stream
my_stream.open("my_file_name",std::fstream::binary | std::fstream::in | std::fstream::out);
if(!my_stream)
{
my_stream.open("my_file_name",std::fstream::binary | std::fstream::trunc | std::fstream::out);
my_stream.close();
// re-open with original flags
my_stream.open("my_file_name",std::fstream::binary | std::fstream::in | std::fstream::out);
}
else
{
// read something
}
// read/write here
Author by
herzl shemuelian
Updated on May 08, 2020Comments
-
herzl shemuelian almost 4 years
I am trying to use std::fstream for io to file, and I want to create the file if it doesn't already exist.
std::fstream my_stream my_stream.open("my_file_name",std::fstream::binary | std::fstream::in | std::fstream::out); if(!my_stream) std::cout<<"error"<<strerror(errorno);
I get this result: "No such file or directory."
How can I create the file in this case?