Sscanf segmentation fault

Question

Sscanf gives an error, take this code:

char * args = malloc(100); strcpy(args, "Simple_str 123"); char * str; int num = 0; sscanf(args, "%s %d", str, &num); printf("%s %d", str, num);

Conclusion: Simple_str 123

It seems to be the way it should be, ok, let's take this code:

 char * args = malloc(100); strcpy(args, "Simple_str 123"); char * str; int num = 0; sscanf(args, "%s %d", str, &num); // <--- ошибка здесь printf("%s %d", str, num); memset(args, 0, 100); strcpy(args, "Simple_str"); sscanf(args, "%s", str); // <--- иногда здесь printf("%s; %s\n", args, str);

How it works?

I compile: gcc -std=c99 main.c

Accepted Answer · 2019-01-29T21:51:08

Both options are grossly erroneous. str is a pointer pointing to nowhere. And you are trying to write something through it. So it turns out "Segmentation fault".

@ I am in despair: ... and not "I am in despair", but "I am in despair."

Sscanf segmentation fault

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