XCode C++ missing sperm()

Question

I'm using C++ and XCode to create a cmd line app to save file permissions, however I can't get the sperm() method to be identified, the error is

'Use of undeclared identifier 'sperm'

My includes and the piece of code in question are below ...

// My includes ...
#include <iostream>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>
#include <vector>
#include <sys/stat.h>
#include <dirent.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <locale.h>
#include <langinfo.h>
#include <stdint.h>

// Code fragment ...

dp = opendir ("/var/someplace");
if (dp != NULL)
{
    while ((ep = readdir (dp)))
    {

        oFile = new FileObject;

        oFile->setName( ep->d_name );
        oFile->setIsDirectory( ep->d_type == isFolder );

        oFiles.push_back (*oFile);            
        // If it's a folder then we can get it's innards 

        if (stat(ep->d_name, &statbuf) == -1)
            continue;
        cout << "%10.10s", sperm(statbuf.st_mode);

        iFile++;
    }



    closedir (dp);
}
else
    perror ("Couldn't open the directory");

Answer 1

This might make me look like a pervert, but I searched google for 'sperm' (ofcourse only for .h and .cpp files). The bad news is I can't find any references to it (except on the stat function page itself).

The good news is I found this piece of code which defines it's own 'sperm' function:

char const * sperm(__mode_t mode) {
    static char local_buff[16] = {0};
    int i = 0;
    // user permissions
    if ((mode & S_IRUSR) == S_IRUSR) local_buff[i] = 'r';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IWUSR) == S_IWUSR) local_buff[i] = 'w';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IXUSR) == S_IXUSR) local_buff[i] = 'x';
    else local_buff[i] = '-';
    i++;
    // group permissions
    if ((mode & S_IRGRP) == S_IRGRP) local_buff[i] = 'r';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IWGRP) == S_IWGRP) local_buff[i] = 'w';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IXGRP) == S_IXGRP) local_buff[i] = 'x';
    else local_buff[i] = '-';
    i++;
    // other permissions
    if ((mode & S_IROTH) == S_IROTH) local_buff[i] = 'r';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IWOTH) == S_IWOTH) local_buff[i] = 'w';
    else local_buff[i] = '-';
    i++;
    if ((mode & S_IXOTH) == S_IXOTH) local_buff[i] = 'x';
    else local_buff[i] = '-';
    return local_buff;
}

usage is simple:

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

int main(int argc, char ** argv)
{
    std::cout<<sperm(S_IRUSR | S_IXUSR | S_IWGRP | S_IROTH)<<std::endl;
    std::cout<<sperm(S_IRUSR)<<std::endl;
    std::cout<<sperm(S_IRUSR | S_IRGRP | S_IWOTH | S_IROTH)<<std::endl;
    return 0;
}

output on ideone:

r-x-w-r--
r--------
r--r--rw-

Answer 2

I ran into this a couple years ago. I don't feel like tiptoeing my way through Google with that particular search term at the moment, but if I remember correctly, the answer is that sperm() is a non-standard system function available on Solaris. But since it's not part of the unix standard, you won't find it on OS X.

Answer 3

Assuming the function is defined (and I'm not going to google that name from work), you have a problem with the way you're printing it:

cout << "%10.10s", sperm(statbuf.st_mode);

That's not going to print a formatted string, since C++ iostreams don't work like C's printf. You could either not format it:

cout << sperm(statbuf.st_mode);

or use printf:

printf("%10.10s", sperm(statbuf.st_mode));

or do some jiggery-pokery with iostream manipulators.