Return dynamically allocated memory from C++ to C

Question

I have a dll that must be useable from C etc, so I cant use string objects etc as a normal would, but I\'m not sure on how to do this safely..

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Answer 1

Over the years C boiled this down to 2 standard methods:

• Caller passes in buffer.
  There are three versions of this.
  Version 1: Pass a buffer and a length.
  Version 2: Documentation specifies an expected min buffer size.
  Version 3: Pre-Flight. Function returns the min buffer required. caller calls twice first time with a NULL buffer.
  • Example: read()
• Use a static buffer that is valid until the next call.
  • Example: tmpname()

A few non standard ones returned memory that you had to explicitly free

• strdup() pops to mind.
  Common extension but not actually in the standard.