Question

I make some research in order to look for the sscanf() source code . But I could not find the answer to my question.

when we use sscanf() in this way:

char str[50] = "5,10,15";
int x;
sscanf(str,"%d,%s",&x,str);

Does sscanf() support “recursive” buffer str ?

Answer 1

It doesn’t break from self modifying buffer. But to make it (tail)recursive, you’d have to read to the end of the string.
The code fragment:

char str[]="5,10,15";
int a[10]={0},x = 0; 
while (sscanf(str,"%d,%s",a+ x++,str)>1);

reads all the integers.

Since this is not really recursive and the string to be read doesn’t overwrite the asciiz in the string, I believe this is “safe” in the meaning: only try this at home.