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Programming-Idioms

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  • Perl

Idiom #107 Get folder containing current program

Assign to string dir the path of the folder containing the currently running executable.
(This is not necessarily the working directory, though.)

use English qw($EXECUTABLE_NAME);
use Path::Tiny qw(path);

my $dir = path($EXECUTABLE_NAME)->parent;

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <linux/limits.h>
#include <libgen.h>

int main()
{
    char exe[PATH_MAX], real_exe[PATH_MAX];
    ssize_t r;
    char *dir;

    if ((r = readlink("/proc/self/exe", exe, PATH_MAX)) < 0)
      exit(1);
    if (r == PATH_MAX)
	r -= 1;
    exe[r] = 0;
    if (realpath(exe, real_exe) == NULL)
	exit(1);
    dir = dirname(real_exe);
    puts(dir);
}

If the executable file that the current process is executing can be found searching $PATH, this is easier, but the general case can still be handled by examining where the symlink file /proc/self/exe points to.
New implementation...
< > ⌨
programming-idioms.org 
my $dir = path($EXECUTABLE_NAME)->parent;

int main()
{
    char exe[PATH_MAX], real_exe[PATH_MAX];
    ssize_t r;
    char *dir;

    if ((r = readlink("/proc/self/exe", exe, PATH_MAX)) < 0)
      exit(1);
    if (r == PATH_MAX)
	r -= 1;
    exe[r] = 0;
    if (realpath(exe, real_exe) == NULL)
	exit(1);
    dir = dirname(real_exe);
    puts(dir);
}

dir = AppDomain.CurrentDomain.BaseDirectory;

void main(string[] args) {
    string dir = args[0].dirName;
}
programPath := os.Args[0]
absolutePath, err := filepath.Abs(programPath)
if err != nil {
	return err
}
dir := filepath.Dir(absolutePath)
dir <- takeDirectory `fmap` getExecutablePath
dir = unsafePerformIO (takeDirectory `fmap` getExecutablePath)
const dir = path.resolve();
const dir = __dirname;
dir = arg[1]
$dir = realpath(dirname(__FILE__));
dir := extractfilepath(paramstr(0));
dir := GetCurrentDir;
dir = os.path.dirname(os.path.abspath(__file__))
dir = str(Path(__file__).parent)
dir = __dir__
let dir = std::env::current_exe()?
    .canonicalize()
    .expect("the current exe should exist")
    .parent()
    .expect("the current exe should be a file")
    .to_string_lossy()
    .to_owned();