std::basic_ios::copyfmt
| basic_ios& copyfmt(const basic_ios& other);
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Copies the state of the stream other into *this. This is done in the following sequence:
1) Calls every callback registered by register_callback() passing erase_event as parameter
2) Copies all member objects from other to *this except for rdstate(), the exception mask, and rdbuf(). In particular, makes copies of the locale, the formatting flags, the contents of the arrays ios_base::iword and ios_base::pword (but not the iword and pword pointers themselves), the callbacks, and the tied stream.
3) Calls every callback registered by register_callback() passing copyfmt_event as parameter
4) Copies the exception mask from other to *this as if by calling exceptions(rhs.except())
Contents |
[edit] Parameters
| other | - | another stream to use as source |
[edit] Return value
*this
[edit] Notes
The second pass through the callbacks may be used to deep-copy the user-defined objects pointed to by the pointers in ios_base::pword
copyfmt() may be used to save and restore the state of a stream. Boost provides a more fine-grained IO state savers library for the same purpose.
[edit] Example
makes the ofstream object "out" behave exactly like std::cout, including formatting, tie() to std::cin, etc.
#include <iostream> #include <fstream> int main() { std::ofstream out; out.copyfmt(std::cout); // copy everything except rdstate and rdbuf out.clear(std::cout.rdstate()); // copy rdstate out.basic_ios<char>::rdbuf(std::cout.rdbuf()); // share the buffer out << "Hello, world\n"; }
Output:
Hello, world