[SOLVED] open new or existing file and write to it. not working like I need it too.

BW-userx · 10-14-2019, 01:57 PM

If I witre it that standard example way to open a file that works, but if I tell it to open a file using a path gotten from code, it does not work. the program does not fail (exit) on a file that is not there, it continues to run even thought it did not actually create and or open an existing file by the same name.

I get user home dir via what is in the code, add that path to a file name open the file, that is not there. it creates it (supposedly). but when I look it is not there at all.

Code:

   
	struct passwd *p;
	char *uhome = NULL;
	uid_t  uid;

  if ((p = getpwuid(uid = getuid())) == NULL)
    perror("getpwuid() error");
  else {
		uhome = p->pw_dir;
	}
	char configfile[21] = "/mhsetrootimagefile";
	strcat(uhome,configfile);
	
	FILE *fptr;

	// this one not working -> //fptr = fopen("uhome", "wr+");
	


fptr = fopen("ThisFile", "w+");
	if (fptr == NULL) {
		fprintf(stderr,"cannot open config file\n");
		exit(1);
	}
	printf("file = %s\n",uhome);

Code:

file = /home/userx/mhsetrootimagefile

[userx@FreeBSD12 ~]$ ls /home/userx/mhsetrootimagefile
ls: /home/userx/mhsetrootimagefile: No such file or directory

what is the proper way to cause the code to create if not there or open if there in a specified location?

IT is not because in here that code is commented out.

NevemTeve · 10-14-2019, 02:29 PM

Code:

fptr = fopen("uhome", "w+");

This will create a file called "uhome" in the current working directory. But if fptr==NULL, then perror(3) explains the problem.

BW-userx · 10-14-2019, 02:44 PM

Quote:

Originally Posted by NevemTeve

Code:

fptr = fopen("uhome", "w+");

This will create a file called "uhome" in the current working directory. But if fptr==NULL, then perror(3) explains the problem.

I didn't think of looking for something like that.. and yep I just did and its there. Let me go scratch my head on this..

thanks..

back... that didnt take long..

Code:

fptr = fopen(uhome, "wr+");

remove quotes, it should show that how to open write to file thing in C is not my strong point.
thanks for pointing that out, now that part is working.