Thread: Dup2() help

I'm having issues with dup2(). I can write to a file, however it's classified as no read, no write. I want it to be read-only.

I think I have what I need in this excerpt.
graph[i] is an array holding structs
graph[i].prog is a string of OS commands ie ls, echo.
graph[i].output is the file to write to.

Code:

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#define CREATE_FLAGS (O_RDWR | O_CREAT | O_APPEND)

 int fileOut=open(graph[i].output, CREATE_FLAGS);
      if(fileOut==-1) {
	perror("Failed to open file");
	return 1;
      }
      
      if(dup2(fileOut, STDOUT_FILENO)==-1) {
	perror("Failed to redirect standard output");
	return 1;
      }


     pid_t childpid;
         
     childpid=fork();
      
      //Fail to fork
      if (childpid==-1) {
	perror("Failed to fork");
	return 1;
      }
      
      //Entered Child
      if (childpid==0) {
	int numArgs;
	char **args;
	numArgs=makeargv(graph[i].prog," ", &args);
	execvp(args[0],args);
	//	fileOut=close(*graph[i].output);
	perror("Child failed to exec\n");
	return 1;
      }

Any help would be appreciated, thank you.

So what actual message does your perror line print?

Also, the combination of O_RDWR with O_APPEND seem weird.