芝生頭の青狼さん

include/linux/moduleparam.h

75 /* Helper functions: type is byte, short, ushort, int, uint, long,
76    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,
77    param_set_XXX and param_check_XXX. */
78 #define module_param_named(name, value, type, perm)                        \
79         param_check_##type(name, &(value));                                \
80         module_param_call(name, param_set_##type, param_get_##type, &value, perm); \
81         __MODULE_PARM_TYPE(name, #type)
82
83 #define module_param(name, type, perm)                          \
84         module_param_named(name, name, type, perm)

매크로에서 ##은 문자열로 그대로 치환 한다는 의미이다 따라서 module_param함수의 두번째 매개변수 type에 주어진 문자열은 그대로 module_param_named로 다시 param_set##type, param_get_##type에 치환된다.

매크로 함수로 정의 되어있는 module_param함수의 두번째 매개변수는 다음과 같이 정의 되어 있다.

101 /* All the helper functions */
102 /* The macros to do compile-time type checking stolen from Jakub
103    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
104 #define __param_check(name, p, type) \
105         static inline type *__check_##name(void) { return(p); }
106
107 extern int param_set_byte(const char *val, struct kernel_param *kp);
108 extern int param_get_byte(char *buffer, struct kernel_param *kp);
109 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
110
111 extern int param_set_short(const char *val, struct kernel_param *kp);
112 extern int param_get_short(char *buffer, struct kernel_param *kp);
113 #define param_check_short(name, p) __param_check(name, p, short)
114
115 extern int param_set_ushort(const char *val, struct kernel_param *kp);
116 extern int param_get_ushort(char *buffer, struct kernel_param *kp);
117 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
118
119 extern int param_set_int(const char *val, struct kernel_param *kp);
120 extern int param_get_int(char *buffer, struct kernel_param *kp);
121 #define param_check_int(name, p) __param_check(name, p, int)
122
123 extern int param_set_uint(const char *val, struct kernel_param *kp);
124 extern int param_get_uint(char *buffer, struct kernel_param *kp);
125 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
126
127 extern int param_set_long(const char *val, struct kernel_param *kp);
128 extern int param_get_long(char *buffer, struct kernel_param *kp);
129 #define param_check_long(name, p) __param_check(name, p, long)
130
131 extern int param_set_ulong(const char *val, struct kernel_param *kp);
132 extern int param_get_ulong(char *buffer, struct kernel_param *kp);
133 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
134
135 extern int param_set_charp(const char *val, struct kernel_param *kp);
136 extern int param_get_charp(char *buffer, struct kernel_param *kp);
137 #define param_check_charp(name, p) __param_check(name, p, char *)
138
139 extern int param_set_bool(const char *val, struct kernel_param *kp);
140 extern int param_get_bool(char *buffer, struct kernel_param *kp);
141 #define param_check_bool(name, p) __param_check(name, p, int)
142
143 extern int param_set_invbool(const char *val, struct kernel_param *kp);
144 extern int param_get_invbool(char *buffer, struct kernel_param *kp);
145 #define param_check_invbool(name, p) __param_check(name, p, int)

소스코드 출처 : lxr.linux.no