C modify char** with strcpy

Question

I'm a little bit confused with pointers at the moment, could someone explain to me the reason why attempting to change a char** with strcpy() causes a segmentation fault?

void *change_string(char **string) {
 char *add = "Changed!";
 strcpy(*string, add);
 return 0;
}

int main() {
 char *p = "Original-";
 change_string(&p);
 printf("%s",p);
}

`char *p = "Original-"` should be `char *p = strdup("Original-")`, if not , modifying `p` is an *undefined behavior* — dvhh, Jul 26 '16 at 09:16

score 1 · Answer 1 · edited Sep 14 '17 at 04:40

1

Your pointer p points to a string literal and you modify that string when you call strcpy(3). Modifying a string literal is undefined behavior.

edited Sep 14 '17 at 04:40

Jonathan Leffler

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answered Jul 26 '16 at 09:21

blatinox

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C modify char** with strcpy

1 Answers1