std::strstreambuf::setbuf
From cppreference.com
< cpp | io | strstreambuf
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protected
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virtual streambuf* setbuf( char * s, std::streamsize n ) ; |
(deprecated in C++98) (removed in C++26) |
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If s is a null pointer and n is zero, this function has no effect.
Otherwise, the effect is implementation-defined: some implementations do nothing, while some implementations deallocate the dynamic member array used as the buffer and begin using the user-supplied character array of size n, whose first element is pointed to by s
This function is protected virtual, it may only be called through pubsetbuf() or from member functions of a user-defined class derived from std::strstreambuf.
Parameters
| s | - | pointer to the first byte in the user-provided buffer |
| n | - | the number of bytes in the user-provided buffer |
Return value
this
Example
Implementation test to check if setbuf() is supported on a dynamic strstream (output obtained with Sun Studio):
Run this code
#include <iostream> #include <strstream> int main() { char a[100] = {}; std::strstream str; str.rdbuf()->pubsetbuf(a, sizeof a); str << "Test string" << std::ends; std::cout << "user-provided buffer holds \"" << a << "\"\n"; }
Possible output:
user-provided buffer holds "Test string"
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
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| LWG 66 | C++98 | the effect of setbuf() was "performs an operation that isdefined separately for each class derived from strstreambuf",but there are no classes derived from strstreambuf
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the effect is implementation-defined |
See also
| invokes setbuf()
(public member function of std::basic_streambuf<CharT,Traits>)
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[virtual]
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replaces the buffer with user-defined array, if permitted (virtual protected member function of std::basic_streambuf<CharT,Traits>) |
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[virtual]
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attempts to replace the controlled character sequence with an array (virtual protected member function of std::basic_stringbuf<CharT,Traits,Allocator>) |
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[virtual]
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provides user-supplied buffer or turns this filebuf unbuffered (virtual protected member function of std::basic_filebuf<CharT,Traits>) |