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The following Standard Template Library functions are guaranteed to leave the moved-from object in a well-specified state.

Several generic standard template library (STL) algorithms, such as std::remove() and std::unique(), remove instances of elements from a container without shrinking the size of the container. Instead, these algorithms return a ForwardIterator to indicate the partition within the container after which elements are no longer valid. The elements in the container that precede the returned iterator are valid elements with specified values; whereas the elements that succeed the returned iterator are valid but have unspecified values. Accessing unspecified values of elements iterated over results in unspecified behavior. Frequently, the erase-remove idiom is used to shrink the size of the container when using these algorithms.

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#include <iostream>
#include <string>

void g(std::string &&v) {
  std::cout << v << std::endl;
}

void f() {
  std::string s;
  for (unsigned i = 0; i < 10; ++i) {
    s.append(1, static_cast<char>('0' + i));
    g(std::move(s));
  }
}

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#include <iostream>
#include <string>

void g(std::string &&v) {
  std::cout << v << std::endl;
}

void f() {
  for (unsigned i = 0; i < 10; ++i) {
    std::string s(1, static_cast<char>('0' + i));
    g(std::move(s));
  }
}

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The state of a moved-from object is generally valid, but unspecified. Relying on unspecified values can lead to abnormal program termination as well as data integrity violations.

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Bibliography

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