C program strange error

[ar1]

Hi, I wrote the following code which creates a simple shell (like bash). It works fine, can take a command along with arguments and run it or give error if it doesn't exist. However, the strange problem is that it doesn;t execute anything the first time "enter" is hit!! But after that it works perfectly.

I couldn't find the bug, any help would be great. Thanks
---------------------------------------------------------------------------------------------

#include <string.h>
#include <errno.h>

#define TRUE 1

void type_prompt();
void *read_command(char *argv[]);
int n = 0;

int main(int argc, char *argv[], char *envp[])
{
char *command;
int status;
argv[0] = NULL;

while (TRUE) /* repeat forever */
{
type_prompt(); /* display prompt on screen */
read_command(argv); /* read input from terminal */

if (fork() != 0) /* fork off child process */
{
waitpid(-1, &status, 0); /* wait for child to exit */
}
else
{
if (execve(argv[0], argv, envp) == -1) /* execute command */
printf("Ouch, can't execute: %s\n", strerror(errno));
}
}
return 0;
}

void type_prompt()
{
printf("[arajgarh]$ ");
}

void *read_command(char *argv[])
{
n = 0;
char temp[256];

gets(temp);
argv[n++] = strtok (temp," ");

while (argv[n-1] != NULL)
argv[n++] = strtok (NULL, " ");
}

[Salem]

Well the first problem is, your code is poorly (ie not at all) indented.

> read_command(argv);
You re-use argv in an entirely inappropriate manner
It also returns void* for no good reason (you don't return anything, and it's ignored anyway)

> gets(temp);
Read the FAQ - it explains why gets() is the world's most dangerous function

> char temp[256];
This is a local variable - image that it's contents will be trashed as soon as the function exits.
Bad news for all those pointers you extracted using strtok

[itsme86]

You obviously didn't bother to heed my advice when you posted this exact same thing on linuxquestions.org about fixing all the warnings and getting rid of gets().

[ar1]

Thanks for helping. Now I understand the issue about temp being local and causing problems.

itsme86, thanks for your code in linuxquestions.org.
Heeding the advice about warnings and gets() was one thing, but I also needed to know WHY the current one is not working, and now I know