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copied!<p>Easy enough with <code>std::string</code>:</p> <pre><code>std::string foo = "C++"; auto bar = "this is a " + foo + " example."; </code></pre> <p>Just make sure one of the first two operands is a <code>std::string</code>, not both <code>const char *</code> or something.</p> <hr> <p>As noted below, this result is being used in <code>CreateProcess</code> as a <code>char *</code> (<code>LPSTR</code>) argument. If the argument was <code>const char *</code>, <code>c_str()</code> would be perfectly acceptable to pass in. However, it is not, which means you should assume it modifies the string. MSDN says this:</p> <blockquote> <p>The Unicode version of this function, CreateProcessW, can modify the contents of this string.</p> </blockquote> <p>Since this is <code>char *</code>, it's evidently using <code>CreateProcessA</code>, so I'd say a <code>const_cast<char *></code> <em>should</em> work, but it's better to be safe.</p> <p>You have two main options, one for C++11 and later, and one for pre-C++11.</p> <h3>C++11</h3> <p><code>std::string</code>'s internal buffer is now guaranteed to be contiguous. It's also guaranteed to be null-terminated. That means you can pass a pointer to the first element:</p> <pre><code>CreateProcess(..., &str[0], ...); </code></pre> <p>Make sure the function only overwrites indices within [0, size()) in the internal array. Overwriting the guaranteed null-terminator is not good.</p> <h3>C++03</h3> <p><code>std::string</code> is not guaranteed to be contiguous or null-terminated. I find it best to make a temporary <code>std::vector</code>, which guarantees the contiguous part, and pass a pointer to its buffer:</p> <pre><code>std::vector<char> strTemp(str.begin(), str.end()); strTemp.push_back('\0'); CreateProcess(..., &strTemp[0], ...); </code></pre> <p>Also note MSDN again:</p> <blockquote> <p>The system adds a terminating null character to the command-line string to separate the file name from the arguments. This divides the original string into two strings for internal processing.</p> </blockquote> <p>That seems to suggest that the null-terminator here isn't necessary, but there's no size parameter, so I'm not completely sure.</p>

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