Currently I use something like:
#include <sys/stat.h>
#include "My_Class.h"
void My_Class::my_function(void)
{
std::ofstream my_file;
struct stat file_info;
if ( filename_str.compare("")!=0 &&
stat(filename_str.c_str(),&file_info) == 0 )
{
my_file.open(filename_str.data(),std::ios::trunc);
//do stuff
my_file.close();
}
else if ( filename_str.compare("")==0 )
{
std::cout << "ERROR! ... output filename not assigned!" << std::endl;
}
else
{
std::cout << "ERROR! File :" << std::endl
<< filename_str << std::endl
<< "does not exist!!" << std::endl;
}
}
...is this a decent way to go, or is there a better alternative? Seems like I could run amuck of permissions if I don't have permissions to read the file.
This is NOT a homework, question, it is a question about best practice.
I'd use the boost::filesystem constructs. Not only are they cross platform, they're part of the next standard library.
Generally I think it is best to just try opening it and catch an error.
IMO, checking permissions is unwise because what if it's a Linux box and you check its attributes, decide you can't write to it, but the filesystem supports ACL's and they do grant you permission? (As a sysadmin I can't stand when apps do this. I like ACL's and if you're an app, don't tell me you can't write to a file unless you've tried first.)
Conceptually, I'd say it depends on what you're planning to do with that file..
So as a best practice, I'd suggest to open files sparingly (ie, if you're not immediately interested in the contents, contend yourself with file attribute-based information), AND handle failure strictly in response to the actual call that opens the file when you need it.
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