Okay so I am trying to pass a char pointer to another function. I can do this with an array of a char but cannot do with a char pointer. Problem is I don't know the size of it so I cannot declare anything about the size within the main()
function.
#include <stdio.h>
void ptrch ( char * point) {
point = "asd";
}
int main() {
char * point;
ptrch(point);
printf("%s\n", point);
return 0;
}
This does not work however, these two works:
1)
#include <stdio.h>
int main() {
char * point;
point = "asd";
printf("%s\n", point);
return 0;
}
2)
#include <stdio.h>
#include <string.h>
void ptrch ( char * point) {
strcpy(point, "asd");
}
int main() {
char point[10];
ptrch(point);
printf("%s\n", point);
return 0;
}
So I am trying to understand the reason and a possible solution for my problem
This should work since pointer to the char pointer is passed. Therefore any changes to the pointer will be seen outside thereafter.
void ptrch ( char ** point) {
*point = "asd";
}
int main() {
char * point;
ptrch(&point);
printf("%s\n", point);
return 0;
}
void ptrch ( char * point) {
point = "asd";
}
Your pointer is passed by value, and this code copies, then overwrites the copy. So the original pointer is untouched.
P.S. Point to be noted that when you do point = "blah"
you are creating a string literal, and any attempt to modify is Undefined behaviour, so it should really be const char *
To Fix - pass a pointer to a pointer as @Hassan TM does, or return the pointer as below.
const char *ptrch () {
return "asd";
}
...
const char* point = ptrch();
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