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C++/Linux Getting Users home directory/ Checking dev drivers

Posted on 2003-11-21
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Last Modified: 2012-06-21
Gday All,


I have a few problems programming in linux/C++ that a just cant seem to find a answer for on the net.
I am using Kylix 3 pro and its help also hasent helped.

Problem 1:
I need to get the path of the user that has executed my program.
For example i need to do the following code

      char* homePath = USERS HOME DIR?
       FILE *outFile;
      outFile = fopen(homePath, "w");
     
      etc..

Problem 2:

Is there an easy method of checking weather or not dev files are resedent?

I have a set of serial card drivers have been installed on the system and i need to check wether or not they have been installed.

The drivers have two dev files.
/dev/esccp0 and  /dev/esccp1.

I have tried to use a fopen and a fstatus on these files to see if they are there, with no luck.
fopen returns NULL evan when they are peresent.

any help would be great

regards,
Michael
 
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Question by:__Michael__
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3 Comments
 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 9801442
Problem 1:
The home directory of a user on a UNIX (or Linux) system is always ~<username>/
So if you want to get the home directory for the user "test", and open a file named "myfile" in this home dir, you would use the following path: "~test/myfile"

Problem 2:
You should be able to use fstat() to find out if a file is a device. The st_mode field in the returned structure does contain this information (test for S_IFBLK and S_IFCHR).
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LVL 86

Accepted Solution

by:
jkr earned 440 total points
ID: 9801447
>>     char* homePath = USERS HOME DIR?

     char* homePath = getenv("HOME");

You can simply evaluate and rely on that environment varaible, it will always be set.

>>Is there an easy method of checking weather or not dev files are resedent?
>>/dev/esccp0 and  /dev/esccp1.

You are referring to "special files", not drivers. Just use 'stat()' to check for their existance:

#include <sys/types.h>
#include <sys/stat.h>

struct stat st;

if ( -1 == stat ( "/dev/esccp0", &st) {

    // does not exist

} else {

    // exists
}

0
 

Author Comment

by:__Michael__
ID: 9801758
Thankyou jkr.

Probems now solved.

Sometimes it the simple things that take the longest!

regards,
Michael
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