snprintf函数的使用

#include <stdio.h>

int snprintf(char *str, size_t size, const char *format, ...);

 Return value
       Upon successful return, these functions return the number of characters printed (excluding the null byte used to end output to strings).

       注意The  functions  snprintf()  and vsnprintf() do not write more thansize bytes (including the terminating null byte ('\0'))

实例：

       截取账单号123456789 放到bill_no中

#define BILL_NO_SIZE 10

char bill_no[BILL_NO_SIZE];

char *bill_src_path="Out_123456789_yyyyMMddHHmmssSSS.spc"

snprintf(bill_no, BILL_NO_SIZE, "%s", strstr(bill_src_path, "Out_") + strlen("Out_"));  最后一字节放\0

printf("billno=%s\n",billno);

打印结果 123456789