error: implicit declaration of function 'create_proc_read_entry' [-Werror=implicit-function-declaration]

Question

I\'m trying to compile a kernel module on kernel 3.13 and I get this error:

error: implicit declaration of function \'create_proc_read_entry\' [-Werror=impli         


        

Answer 1

In your linux version 3.13 create_proc_read_entry this method has been deleted,instead using proc_create or proc_create_data.You can use this API

struct proc_dir_entry *proc_create_data(const char *, umode_t,
                       struct proc_dir_entry *,
                       const struct file_operations *,
                       void *);

static inline struct proc_dir_entry *proc_create(
         const char *name, umode_t mode, struct proc_dir_entry *parent,
         const struct file_operations *proc_fops);

Answer 2

in Linux 3.9

static inline struct proc_dir_entry *create_proc_read_entry(const char *name,
                                                            umode_t mode, 
                                                            struct proc_dir_entry *base, 
                                                            read_proc_t *read_proc, 
                                                            void * data
                                                           ) { return NULL; }

http://lxr.free-electrons.com/source/include/linux/proc_fs.h?v=3.9

in Linux 3.10

static inline struct proc_dir_entry *proc_create(const char *name, 
                                                 umode_t mode, 
                                                 struct proc_dir_entry *parent,
                                                 const struct file_operations *proc_fops
                                                )

http://lxr.free-electrons.com/source/include/linux/proc_fs.h?v=3.10

So change create_proc_read_entry() to proc_create(), and change the 5 parameters to 4 parameters. It then works.

Answer 3

The error is because you are not including explicitly the header that declares the function and the compiler is 'including' implicitily for you and this throws a warning. The flag '-Werror' is making the compiler treats the warning as an error. Try adding: #include <linux/proc_fs.h>

Also: create_proc_read_entry is a deprecated function.

Take a look at: https://lkml.org/lkml/2013/4/11/215