查看文档(man 3snprintf)说明也证明了这点。 上面的内容还说,如果返回值等于或者大于size,则表明输出字符串被截断了(truncated)。在项目中也经常用到这个特性进行异常判断,下面就是项目中所用网路框架中的源码,正是因为这段代码才导致自己去查阅相关的资料去弄清楚这个小细节。
If snprintf returns a value > count - 1, the output has been truncated. The _snprintf family of functions only appends a terminating NULL character if the formatted string length is strictly less than count characters. Each argument (if any) is converted and is output acco...
printf("warning:sting will be truncated"); sa[sizeof(sa)-1]=0; } === int snprintf(char *restrict buf, size_t n, const char * restrictformat, ...); 函数说明:最多从源串中拷贝n-1个字符到目标串中,然后再在后面加一个0。所以如果目标串的大小为n 的话,将不会溢出。 函数返回值:若成功...
printf("warning:string will be truncated"); sa[sizeof(sa)-1]=0; } 2. char sa[256]={0}; int result = _snprintf(sa,sizeof(sa),"%s",sb); if(result==sizeof(sa) || result<0) { printf("warning:sting will be truncated"); sa[sizeof(sa)-1]=0; } === int snprintf(char *...
char sa[256]={0}; int result = _snprintf(sa,sizeof(sa),"%s",sb); if(result==sizeof(sa) || result<0) { printf("warning:sting will be truncated"); sa[sizeof(sa)-1]=0; }
(sa[sizeof(sa)-1]!=0) { printf("warning:string will be truncated"); sa[sizeof(sa)-1]=0; } 2. char sa[256]={0}; int result = _snprintf(sa,sizeof(sa),"%s",sb); if(result==sizeof(sa) || result<0) { printf("warning:sting will be truncated"); sa[sizeof(sa)-1]=0...
Note that if your system already hassnprintf(3)but this implementation was installed anyway, it's because the system implementation has a broken return value. Some older implementations (e.g.glibc-2.0) return -1 when the string is truncated rather than returning the number of...
printf("warning:string will be truncated"); sa[sizeof(sa)-1]=0; } 2. char sa[256]={0}; int result = _snprintf(sa,sizeof(sa),"%s",sb); if(result==sizeof(sa) || result<0) { printf("warning:sting will be truncated"); ...
If the value of the argument is negative, it results with the - flag specified and positive field width (Note: This is the minimum width: The value is never truncated.). (optional) . followed by integer number or *, or neither that specifies precision of the conversion. In the case ...
Ifsnprintfreturns a value >count- 1, the output has been truncated. The_snprintffamily of functions only appends a terminatingNULLcharacter if the formatted string length is strictly less thancountcharacters. Eachargument(if any) is converted and is output according to the correspondi...