Using execv

execv like all other calls of the exec family,creates a new process replacing the current process.

The syntax of execv is

int execv(const char *path, char *const argv[]);

Arguments:

path: path to the executable to be launched by execve argv: Pointer to an array of pointers

The operation is exactly same as that of execve as described in "Usage of execve". The only differece is that execv does not take the third argument

char * const envp[]

Here is an example of using execv :

Let us take a program to print hello world.

hello.c :

#include<stdio.h> main(int argc,char *argv[],char *envp[]){ printf("Filename: %s\n",argv[0]); printf("%s %s\n",argv[1],argv[2]); }

compile this to generate the executable hello

cc hello.c -o hello

Here is a program that will launch the executable hello using execv

#include<stdio.h> #include<stdlib.h> #include<unistd.h> main() { char *temp[] = {NULL,"hello","world",NULL}; temp[0]="hello"; execv("hello",temp); printf("error"); }

Output:

Filename: hello hello world