C - execve function with touch command not working

Question

I am trying to run touch command via execve(), here is my code:

#include <stdio.h>
#include <unistd.h>

int main()
{
char * c[2]={"/usr/bin/touch","test.txt"};
execve(c[0],c,NULL);
return 0;   
} 

But it doesn't seem like the file is being touched or the date isn't being updated. Somebody help me.

Answer 1

The last element of the array needs to be NULL, so that the exec call can figure out the length of the array.

So change

char * c[2]={"/usr/bin/touch","test.txt"};

to

char * c[3]={"/usr/bin/touch","test.txt",NULL};

Answer 2

You can also use system(); function Just put your command line in parameter like :

system("touch test.txt");

or you also can use fopen with flag "a" like :

FILE *fp = fopen("test.txt", "a");

flag "a" open the file passed as paramater (in our case "test.txt" and if it doesn't exist, it is created)

Man system : http://manpagesfr.free.fr/man/man3/system.3.html

Man Fopen : http://manpagesfr.free.fr/man/man3/fopen.3.html

Have a good day!