How to Redirect C STDOUT to a User-Defined Function?

Redirecting C STDOUT to a Custom Function

Redirecting stdout to a file is a common practice, but what if you want to redirect it to a function you define?

For example, consider the following hypothetical case:

<code class="cpp">void MyHandler(const char* data);

// <magical redirection code>

printf("test");
std::cout <p><strong>Solution</strong></p>
<p>As pointed out by @Konrad Rudolph, redirecting stdout to a function is possible using an ostringstream. Here's how you can do it:</p>
<pre class="brush:php;toolbar:false"><code class="cpp">// Redirect cout.
std::streambuf* oldCoutStreamBuf = std::cout.rdbuf();
std::ostringstream strCout;
std::cout.rdbuf(strCout.rdbuf());

// This goes to the string stream.
std::cout <p>While this method works for cout, cerr, and clog, it may not redirect all stdout for functions like printf, which typically target both stdout and stderr streams.</p>
<p>For larger data, more advanced techniques like freopen(), setbuf(), dup(), and dup2() can be employed. These operations require a bit more system-level understanding and may involve creating pipes or manipulating file descriptors.</p></code>

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