Compiler Warning (level 1) C4129

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'character' : unrecognized character escape sequence

The character following a backslash (\) in a character or string constant is not recognized as a valid escape sequence. The backslash is ignored and not printed. The character following the backslash is printed.

To print a single backslash, specify a double backslash (\\).

The C++ standard, in section 2.13.2 discusses escape sequences.

The following sample generates C4129:

// C4129.cpp
// compile with: /W1
int main() {
   char array1[] = "\/709";   // C4129
   char array2[] = "\n709";   // OK
}