How Can a C Class Handle Variable Arguments with printf/sprintf?

Passing Variable Arguments to printf/sprintf

Question:

How can a class define a method that accepts a variable number of arguments and formats them using printf?

Example:

Consider a class with an "error" method:

class MyClass
{
public:
    void Error(const char* format, ...);
};

The Error method should retrieve the variable arguments, format them using printf/sprintf, and perform some action.

Answer:

To accomplish this, use vfprintf:

void Error(const char* format, ...)
{
    va_list argptr;
    va_start(argptr, format);
    vfprintf(stderr, format, argptr);
    va_end(argptr);
}

This outputs the formatted text to stderr. To save the output to a string, use vsnprintf instead. Avoid using vsprintf, as it can cause buffer overflows.

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