Programming a Shell in C, Disappearing char** When Passed to Function - c

Question

I've only found a few threads like this, and none with information that I am able to make any sense of. I'm programming a shell in C and I feel like it should be easy but my C programming is not so fresh. I'm having issues with passing a double pointer and the contents disappearing
I feel I am on the right track, and it sounds like it has something to do with initialization, but I've tried a few things, setting pointers to NULL just to be sure. Thanks.
void runProgram (char **cLine);
char **parse(char *str);
/*
*
*/
int main(int argc, char** argv)
{
char *cin = NULL;
ssize_t buffer = 0;
char **tempArgs = NULL;
printf(">");
while(1)
{
getline(&cin, &buffer, stdin);
tempArgs = parse(cin); //malloc, parse, and return
printf("passing %s", tempArgs[0]); //works just fine here, can see the string
runProgram(tempArgs); //enter this function and array is lost
}
return (EXIT_SUCCESS);
}
char** parse( char* str )
{
char *token = NULL;
char tokens[256];
char** args = malloc( 256 );
int i = 0;
strcpy( tokens, str );
args[i] = strtok( tokens, " " );
while( args[i] )
{
i++;
args[i] = strtok(NULL, " ");
}
args[i] = NULL;
return args;
}
Visible in main up until this function call
void runProgram (char **cLine)
{
//function that calls fork and execvp
}

Answer 1

The simplest fix is not to use tokens at all in the parse() function:
int main(void)
{
char *buffer = NULL;
size_t buflen = 0;
char **tempArgs = NULL;
printf("> ");
while (getline(&buffer, &buflen, stdin) != -1)
{
tempArgs = parse(buffer);
printf("passing %s", tempArgs[0]);
runProgram(tempArgs);
printf("> ");
free(tempArgs); // Free the space allocated by parse()
}
free(buffer); // Free the space allocated by getline()
return (EXIT_SUCCESS);
}
char **parse(char *str)
{
char **args = malloc(256);
if (args == 0)
…handle error appropriately…
int i = 0;
args[i] = strtok(str, " ");
// Bounds checking omitted
while (args[i])
args[++i] = strtok(NULL, " ");
return args;
}
Note that when the loop terminates, the array is already null terminated, so the extra assignment wasn't necessary (but it is better to be safe than sorry).