Variable popen calls in C

Question

I'm trying to execute MS-DOS DEL commands inside a Win32 C program, and I already know that system and popen can be used for this. However, the problem is that both require string literals (type const char) for the commands, and I need something like the DOS equivalent of this Perl code (more or less, don't know if it actually works):

my $user = $ENV{'USERNAME'};
my $directory = $ENV{'HOME'};
my $files = system("dir " . $directory);
my $pattern = "s/(\d{7,8})|(\"" . $user . "\")/";
$files ~= $pattern;
system("rm " . $files);

which obviously has to use string literals for the rm command. Is there some other subprocess function in C that allows for char arrays as arguments for process names?

Answer 1

Its a pain, but you will probably end up having to un-escape all the escape characters. "\blah" -> "\\blah", etc. See a list of them here.

Based on your code, I would do something like (roughly):

pattern = "s/(\\d{7,8})|(\\\"%s\\\")/";
char buff[100];
sprintf(buff, getenv("HOME"));
system(buff);

The idea being specify the pattern with all the troubling characters escaped, i.e \\ and \", then use sprintf to get the final format string. The string from getenv will not have escape character problems, so you can use it directly.