objective c - Some C functions in iOS duplicated as #define -


c functions memcpy , memset available c functions #define in ios:

for example #define memcpy, under hood, is:

#define memcpy(dest, src, len)                  \ ((__darwin_obsz0 (dest) != (size_t) -1)             \  ? __builtin___memcpy_chk (dest, src, len, __darwin_obsz0 (dest))   \  : __inline_memcpy_chk (dest, src, len))

  1. i gather there memory checking here can shed additional details on why better memcpy alone (where value added)?

  2. more importantly, when use which?

unless #undef macro, or call (memcpy)(args...), use macro variant.

i use maco - it's intended fast , efficient, , work expect.


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