Does strlen return same value for a binary and ascii data

问题

Please find the below code snippet.

unsigned char bInput[20];
unsigned char cInput[20];

From a function, I get a binary data in bInput and I determined its length using strlen(bInput). I converted bInput which is in binary to ASCII and stored in cInput and printed its length. But both are different.

I am new to programming. Please guide regarding its behaviour.

回答1:

result wont be same for both cases. Below is one sample scenario: Null is valid UTF-8, it just doesn't work with C 'strings'.

   char temp[8];
   buf = "abcde\0f";

What we have here is a buffer of length 8, which contains these char values:

97 98 99 100 101 0 102 0

here,strlen(temp) is equal to 5 as per strlen design,however,The actual length of the buffer is eight.

回答2:

Function strlen returns the index of the first character in memory with a value of 0 (AKA '\0'), starting from the memory address indicated by the input argument passed to this function.

If you pass a memory address of "something else" other than a zero-terminated string of characters (which has been properly allocated at that memory address), then there's a fair chance that it will result with a memory-access violation (AKA segmentation fault).

回答3:

strlen() counts each byte untill it reaches NULL character ('\0' that means value of a byte is zero). So if you are getting different length for binary and ascii characters means you need to check the below two points in your conversion logic,

what you are doing if binary value is zero.
whether you are converting any nonzero binary value to zero.

来源：https://stackoverflow.com/questions/24596189/does-strlen-return-same-value-for-a-binary-and-ascii-data

标签

string

char

ascii

strlen