This post originated from an RSS feed registered with Agile Buzz by Keith Ray. Original Post: BAd APIs Feed Title: MemoRanda Feed URL: http://homepage.mac.com/1/homepage404ErrorPage.html Feed Description: Keith Ray's notes to be remembered on agile software development, project management, oo programming, and other topics. Latest Agile Buzz Posts Latest Agile Buzz Posts by Keith Ray Latest Posts From MemoRanda

Bad APIs start at the very beginning. For example, the C function alloc(size_t size) - a function to allocate memory in the heap - creates a block of memory; but what does it return? Not a data-structure describing the block, but half of that information, just the pointer. Imagine what could have happened if that function has been defined correctly:

struct MemoryBlock
{
    char*  block_start;
    size_t block_size;
};

MemoryBlock Alloc( size_t sizeIn );

void Free( MemoryBlock * blockIn );

If these two pieces -- pointer and length -- were always kept together, then other data-types implemented in C, like strings could have been safer...

void StringCopy( MemoryBlock* destString, MemoryBlock* sourceString );