c - 如何在 C 中将 char 数组转换为变量 long？

Question

我已经尝试了几个小时来转换它。我试过遍历数组，将字符转换为长整数，但这行不通。我在网上看过一些简单的例子，但它们没有涵盖较长的 char 数组的循环过程。我可以使用什么方法将这个 char 数组 (SAMPLE) 转换为一个 long 类型的变量？

ar.h

struct  ar_hdr       /* file member header */
     {
         char    ar_name[16];    /* '/' terminated file member name */
         char    ar_date[12];    /* file member date */
         char    ar_uid[6]       /* file member user identification */
         char    ar_gid[6]       /* file member group identification */
         char    ar_mode[8]      /* file member mode (octal) */
         char    ar_size[10];    /* file member size */
         char    ar_fmag[2];     /* header trailer string */
     };

我的代码

struct ar_hdr sample;
lseek(fileD, 24, SEEK_SET); //fileD is the file desriptor for the opened archive

//I start at 24 because of the 8 byte magic string for an archive starts the file "!<arch>\n"


int numRead = read(fileD, sample.ar_date, 12);
printf(sample.ar_date);

long epoch = (long *) *sample.ar_date;   //terrible coding here
printf("The current time is: %s\n", asctime(gmtime(&epoch)));

Answer 1

man ar 说:

All information in the file member headers is in printable ASCII. The numeric information contained in the headers is stored as decimal numbers (except for ar_mode which is in octal). Thus, if the archive contains printable files, the archive itself is printable.

所以 atol(ar_date) 应该可以解决问题。