std::ios_base::openmode
From cppreference.com
| typedef /* implementation defined */ openmode; |
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| static constexpr openmode app = /* implementation defined */; static constexpr openmode binary = /* implementation defined */; |
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| static constexpr openmode noreplace = /* implementation defined */; |
(since C++23) | |
Specifies available file open flags. It is a BitmaskType, the following constants are defined:
| Constant | Explanation |
| app | seek to the end of stream before each write |
| binary | open in binary mode |
| in | open for reading |
| out | open for writing |
| trunc | discard the contents of the stream when opening |
| ate | seek to the end of stream immediately after open |
| noreplace (C++23) | open in exclusive mode |
Example
Run this code
#include <fstream> #include <iostream> #include <string> int main() { const char* fname = "unique_name.txt"; // write to a temporary stream object std::fstream(fname, std::ios::out | std::ios::trunc) << "Hi"; std::string s; std::fstream(fname, std::ios::in) >> s; std::cout << s << '\n'; }
Output:
Hi
See also
| opens a file and configures it as the associated character sequence (public member function of std::basic_filebuf<CharT,Traits>) | |
constructs a basic_stringbuf object (public member function of std::basic_stringbuf<CharT,Traits,Allocator>) |