c - 在 C 命令行参数中为 argv 分配的缓冲区大小

Question

当我们编写可以接受命令行参数的 C 程序时，我们将 main 函数编写为:

int main(int argc, char **argv) {
. . .
}

我们知道 argc 大于等于 1所以，至少 argv[0] 存在。我的问题是为 argv[0] 和后续参数分配的缓冲区大小是多少，如果有的话，例如argv[1], argv[2] 等等？

Answer 1

We know argc is greater than equal to 1

嗯，那不是真的。它应该是非负的。也可以为 0。

如果 argv[n] 存在，argv[n] 的大小就是您平台中指针的大小。指针指向的内存大小与提供的命令行参数字符串(由底层环境提供)相同。

引用 C11，章节 §5.1.2.2.1

• The value of argc shall be nonnegative.

和，

• If the value of argc is greater than zero, the array members argv[0] through argv[argc-1] inclusive shall contain pointers to strings, which are given implementation-defined values by the host environment prior to program startup. The intent is to supply to the program information determined prior to program startup from elsewhere in the hosted environment. [...]

• If the value of argc is greater than zero, the string pointed to by argv[0] represents the program name; argv[0][0] shall be the null character if the program name is not available from the host environment. If the value of argc is greater than one, the strings pointed to by argv[1] through argv[argc-1] represent the program parameters.