Allocate Memory for an array of char pointers? (C)

Asked Mar 29 '18 at 20:41

Active Mar 29 '18 at 20:44

Viewed 28 times

I am attempting to layout an array of character pointers from a file. Here is my attempt:

    char c; //in_file is a FILE object
    char** mazestring = malloc(sizeof(char*));
    while((c = fgetc(in_file)) != EOF) {
            mazestring = realloc(mazestring,sizeof(char*)+sizeof(mazestring));
            char *cp = malloc(sizeof(char*));
            *cp = c;
    }

When i wrote this code, i was unsure so pardon the nooby code. I keep getting a seg fault whenever i attempt to run.

asked Mar 29 '18 at 20:41

Adam G.

2

`sizeof(mazestring)` doesn't work/is constant = size of pointer. you have to keep track of the size some other way. – Jean-François Fabre Mar 29 '18 at 20:43
1

Also, there's a memory leak at `char *cp = malloc(sizeof(char*));`. You don't free it. – Ben Mar 29 '18 at 20:44
I did not realize it was the sizeof problem, thank you – Adam G. Mar 29 '18 at 20:50
1

"sizeof" is a compile-time operator. It can't possibly know what you allocate at runtime. – Lee Daniel Crocker Mar 29 '18 at 20:56
`char *cp = malloc(sizeof(char*));` Is wrong. That creates space for the size of a pointer, not the size of a char. – FredK Mar 29 '18 at 21:21

Allocate Memory for an array of char pointers? (C)

0 Answers0