I am declaring an array of strings by using:
char *commands[100];
I then proceed to enter a while loop that reads commands input from the user:
while(getcmd(buf, sizeof(buf), cmd_count) >= 0){
printf(2, "cmd_count: %d\n", cmd_count);
buf[strlen(buf)-1] = 0;
printf(2, "string buf: -%s-\n", buf);
commands[cmd_count] = buf;
printf(2, "commands: %s\n", commands[0]);
printf(2, "commands: %s\n", commands[1]);
printf(2, "commands: %s\n", commands[2]);
printf(2, "commands: %s\n", commands[3]);
cmd_count++;
}
Here is the output from two iterations:
0 EZ$ ls
cmd_count: 0
string buf: -ls-
commands: ls
commands: (null)
commands: (null)
commands: (null)
EZ$ echo hello
cmd_count: 1
string buf: -echo hello-
commands: echo hello
commands: echo hello
commands: (null)
commands: (null)
Even though cmd_count was clearly 1 on the second iteration, it rewrote both the 0th and 1st position. What gives?
Not knowing your entire algorithm, a simple approach may be:
currently you have the variable command allocated to hold 100 char pointers, so that gives you room to handle cmd_count 0 - 99.
but you only have a single buffer for storing each command
if you do need to store each command past the while loop in which you read them, how about the following approach:
allocate a buffer for each pointer in commands that is big enough to hold a command
for (int i = 0; i < 100; i++) {
commands[i] = malloc(MAXSTRINGSIZE + 1);
}
(you could probably optimize this by allocating ((MAXSTRINGSIZE + 1) * 100) and then setting each pointer in commands to the correct offset, but the approach above may be easier for you to understand if you are just learning about pointers)