These flags can be combined with the bitwise OR operator ( |). The output position starts at the end of the file.Īll output operations happen at the end of the file, appending to its existing contents.Īny contents that existed in the file before it is open are discarded. Operations are performed in binary mode rather than text. This is an object of the bitmask member type openmode that consists of a combination of the following member constants:įile open for reading: the internal stream buffer supports input operations.įile open for writing: the internal stream buffer supports output operations. mode Flags describing the requested input/output mode for the file. Specifics about its format and validity depend on the library implementation and running environment. Parameters filename A string representing the name of the file to be opened. The internal filebuf object has at least the same duration as the ofstream object. X is left in an unspecified but valid state. (4) move constructor Acquires the contents of x.įirst, the function move-constructs both its base ostream class from x and a filebuf object from x's internal filebuf object, and then associates them by calling member set_rdbuf. (3) copy constructor (deleted) Deleted (no copy constructor). If the file cannot be opened, the stream's failbit flag is set. Then, filebuf::open is called with filename and mode as arguments. Internally, its ostream base constructor is passed a pointer to a newly constructed filebuf object (the internal file stream buffer).
(2) initialization constructor Constructs an ofstream object, initially associated with the file identified by its first argument ( filename), open with the mode specified by mode. (1) default constructor Constructs an ofstream object that is not associated with any file.
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