pointer to __u32 in a header file

I need to pass a pointer like so

extern int Si4709_dev_chan_get(__u32 *);

but gcc complaints about missing brackets.

Si4709_dev.h:130: error开发者_开发百科: expected ‘)’ before ‘*’ token

any ideas on what I can do?

-Earlence

Maybe you need to include the header that contains the typedef for __u32, this is usually <asm/types.h> or <sys/types.h>.

In anycase they shouldn't be portable, you should rely on something that is more likely to be portable like uint32_t which should be standard for C99 conform implementations (and it should be in stdint.h.

This is an old, probably dead, question, but there seems to be some confusion to what __u32 actually is, but at least in 3.16.1, which is what I'm looking at right now, __u32 is defined in ./include/uapi/asm-generic/int-ll64.h thusly:

typedef unsigned int __u32;

So, it's simply an unsigned integer.

otherwise, your syntax is wrong, since this is a function definition, you need to name the pointer something to reference it within the function:

extern int Si4709_dev_chan_get(__u32 *x);

Otherwise, see this for more.

http://en.wikipedia.org/wiki/Pointer_%28computer_programming%29#Pass-by-address_using_pointers