CODEWITHSUNDEEP
cmacros
systemsfault
systemsfault

Reputation: 15527

Question about a wrapper macro function

I was reading the jemalloc's realloc function and noticed that all the non-static functions(at least the ones I've seen) in jemalloc is wrapped with JEMALLOC_P macro and JEMALLOC_P is:

#define JEMALLOC_P(s) s

Why would they need such a thing?

Upvotes: 0

Views: 1045

Answers (2)

mu is too short
mu is too short

Reputation: 434585

From the jemalloc configure script:

AC_DEFINE_UNQUOTED([JEMALLOC_P(string_that_no_one_should_want_to_use_as_a_jemalloc_API_prefix)], [${JEMALLOC_PREFIX}##string_that_no_one_should_want_to_use_as_a_jemalloc_API_prefix])

I'd guess that it is intended to provide a prefix for all of the jemalloc functions.

You'll also see things like this in jemalloc.h:

void *JEMALLOC_P(malloc)(size_t size)

So, by default, jemalloc takes over the malloc() name but if you need to still use plain malloc() then you could

#define JEMALLOC_P(s) je_##s

and get je_malloc() and plain malloc() at the same time.

Upvotes: 1

Remo.D
Remo.D

Reputation: 16512

You should look at the context that line is in. The code is actually:

#ifndef JEMALLOC_P
#  define JEMALLOC_P(s) s
#endif

This means that, prior to including the header file, you could have provided your version of the JEMALLOC_P(). If you haven't that is the default.

Upvotes: 1

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