unable to find function definition

[Silvan Jegen]

On Tue, Apr 26, 2016 at 11:24:43AM -0400, Valdis.Kletnieks at vt.edu wrote:
> On Tue, 26 Apr 2016 15:31:51 +0200, Silvan Jegen said:
> 
> > A simple but naive approach would be a grep command like this.
> >
> > grep "function_pointer =" `find . -iname '*.c' -o -iname '*.h'`
> 
> Two better ways:
> 
> grep -r "function_pointer =' [A-Za-z]*
> 
> find * -name '*.[ch]' | xargs grep 'function pointer ='
> 
> Hint 1:  Globbing * rather than . is a win at the top level of the
> kernel source, because * won't match .git, which is a gigabyte or so
> of stuff that you don't want to grep through

Good idea!

There may also be cases where there is no space before the assignment so
using a regexp like this may be better.

grep 'function_pointer ?='


> Hint 2: You want -name rather than -iname because there shouldn't be any
> *.C or *.H files in the tree, and avoiding case-insensitive matches is a bit
> faster.

True, this was mostly muscle memory.


> And another winner if you have a git tree (which of course you should):
> 
> git grep 'function_pointer ='

Looks useful but I hope they did not implement their own version of
grep...


> One gotcha is that in some places, the kernel does evil pre-processor
> stuff like:
> 
> #define ATOMIC_LONG_INIT(i)     ATOMIC_INIT(i)
> #define ATOMIC_LONG_PFX(x)      atomic ## x
> 
> #endif
> 
> #define ATOMIC_LONG_READ_OP(mo)                                         static inline long atomic_long_read##mo(const atomic_long_t *l)         {                                                                               ATOMIC_LONG_PFX(_t) *v = (ATOMIC_LONG_PFX(_t) *)l;                                                                                              return (long)ATOMIC_LONG_PFX(_read##mo)(v);                     }
> ATOMIC_LONG_READ_OP()
> ATOMIC_LONG_READ_OP(_acquire)
> 
> (this example from include/asm-generic/atomic-long.h, but similar ## abuse
> happens elsewhere as well...)

Yeah, I don't think there is much you can do about these cases...


Cheers,

Silvan

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