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Full Discussion: Passing argument to command in C
Top Forums Programming Passing argument to command in C Post 302558797 by zacharoni16 on Sunday 25th of September 2011 11:50:40 AM
Old 09-25-2011
You need to take advantage of the complete definition of the main function declarion:
Code:
main() // this wont work for your application

int main(int argc, char *argv[]); // this is what you need


the argc is the argument count, this always has at least one argument passed to it "The program name", so you will need to check if the user entered an argument with something like
Code:
if (argc > 1)
// handle this

I will leave it up to you to research argv

---------- Post updated at 11:50 AM ---------- Previous update was at 11:43 AM ----------

ah misunderstood your question

you need something like this:


put you need to parse your array of strings
Code:
pid_t  pid;
     int    status;

     if ((pid = fork()) < 0) {     /* fork a child process           */
          printf("*** ERROR: Child failedd\n");
          exit(1);
     }
     else if (pid == 0) {          /* for the child process:         */
          if (execvp(*argv, argv) < 0) {     /* execute the command  */
               printf("*** ERROR: exec failed\n");
               exit(1);
          }
     }
     else {                                  /* for the parent:      */
          while (wait(&status) != pid)       /* wait for completion  */
               ;
     }

Last edited by Scott; 09-25-2011 at 01:08 PM.. Reason: Please use code tags
 

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LEARN ABOUT DEBIAN

ns_execargv

Ns_Exec(3aolserver)					   AOLserver Library Procedures 				       Ns_Exec(3aolserver)

__________________________________________________________________________________________________________________________________________________

NAME

       Ns_ExecArgblk,  Ns_ExecArgv,  Ns_ExecProc,  Ns_ExecProcess,  Ns_Fork,  Ns_GetEnviron, Ns_WaitForProcess, Ns_WaitProcess, ns_fork - External
       process execution

SYNOPSIS

       #include "ns.h"

       int
       Ns_ExecArgblk(char *exec, char *dir, int fdin, int fdout,
		     char *args, Ns_Set *env)

       int
       Ns_ExecArgv(char *exec, char *dir, int fdin, int fdout,
		   char **argv, Ns_Set *env)

       int
       Ns_ExecProc(char *exec, char **argv)

       int
       Ns_ExecProcess(char *exec, char *dir, int fdin, int fdout,
		      char *args, Ns_Set *env)

       int
       Ns_Fork(void)

       char
       **Ns_GetEnviron(void)

       int
       Ns_WaitForProcess(int pid, int *statusPtr)

       int
       Ns_WaitProcess(int pid)

       int
       ns_fork(void)
_________________________________________________________________

DESCRIPTION

       These functions handle fork and exec operations. See files: nsd/exec.c, nsd/tclenv.c and nsthread/fork.c.

       Ns_ExecArgblk(exec, dir, fdin, fdout, args, env)

	      Executes a command in a child process. Return process id of child process exec'ing the command or -1 on failure.	Provides  extended
	      error checking and error messages.

       Ns_ExecArgv(exec, dir, fdin, fdout, argv, env)

	      Execute a command in a child process using fork(2) and execve(2), returns the process id of child process exec'ing the command or -1
	      on failure. The child sends an extended error message to the parent.

       Ns_ExecProc(exec, argv)

	      Executes a command in a child process. Returns the process id of the child process exec'ing the command or -1 on	failure.   Simpli-
	      fies call to Ns_ExecArgv.

       Ns_ExecProcess(exec, dir, fdin, fdout, args, env)

	      Executes	a  command  in	a child process. Returns the process id of the child process exec'ing the command or -1 on failure.  Calls
	      Ns_ExecArgblk with same arguments.

       Ns_Fork()
	      Posix style fork(), using fork1() on Solaris if needed. See fork(2) man page. Calls ns_fork.

       Ns_GetEnviron()

	      Returns pointer to the environment vector.

       Ns_WaitForProcess(pid, statusPtr)

	      Wait for child process. Returns NS_OK on success, or NS_ERROR on failure. *statusPtr is set to the exit code of the child process.

       Ns_WaitProcess(pid)

	      Wait for child process. Calls Ns_WaitForProcess with NULL statusPtr. Returns NS_OK on success, or NS_ERROR on failure.

       ns_fork()

	      Posix style fork(), using fork1() on Solaris if needed.

SEE ALSO

       nsd(1), info(n)

KEYWORDS

AOLserver								4.0						       Ns_Exec(3aolserver)
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