linux系統庫函式之strcpy、strncpy
92 /**
93 * strcpy - Copy a %NUL terminated string
94 * @dest: Where to copy the string to
95 * @src: Where to copy the string from
96 */
97 #undef strcpy
98 char *strcpy(char *dest, const char *src)
99 {
100 char *tmp = dest;
101
102 while ((*dest++ = *src++) != '\0')
103 /* nothing */;
104 return tmp;
105 }
106 EXPORT_SYMBOL(strcpy);
107 #endif
strcpy函式為字串拷貝函式，它只能拷貝字串，遇到字串的結束符'/0'拷貝結束。要是沒有這個結束符，後果可想而知。
109 #ifndef __HAVE_ARCH_STRNCPY
110 /**
111 * strncpy - Copy a length-limited, %NUL-terminated string
112 * @dest: Where to copy the string to
113 * @src: Where to copy the string from
114 * @count: The maximum number of bytes to copy
115 *
116 * The result is not %NUL-terminated if the source exceeds
117 * @count bytes.
118 *
119 * In the case where the length of @src is less than that of
120 * count, the remainder of @dest will be padded with %NUL.
121 *
122 */
123 char *strncpy(char *dest, const char *src, size_t count)
124 {
125 char *tmp = dest;
126
127 while (count) {
128 if ((*tmp = *src) != 0)
129 src++;
130 tmp++;
131 count--;
132 }
133 return dest;
134 }
135 EXPORT_SYMBOL(strncpy);
136 #endif
strncpy也是字串拷貝函式，遇到字串結束符就停止拷貝，但它和strcpy不同的是，如果沒有遇到字串結束符，它只拷貝count位元組大小資料。有兩種用途，一是，我只需要count位元組大小資料，二是，如果拷貝的資料沒有字串結束符，它還可以自己結束資料拷貝。