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

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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.

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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