How to pass a const char* pointer to fts_open()

Question

How does one pass a const char *path to fts_open? I would like to pass a filePath.

Answer 1

I assume you want to know how to pass this single path to the argv (type char const **) parameter of fts_open. This parameter is described thus:

argv

Is a NULL terminated array of character pointers naming one or more paths that make up the file hierarchy.

So you need to create an array of length two whose elements are of type char*. Put your path in the first element and put NULL in the second element. Like this:

char const *argv[] = { path, NULL };

You can now pass argv to fts_open.

Answer 2

fts_open expects an array of char* to be compatible with the main function’s argv array (and since char** can’t be converted to char const**).

So you need to create such an array. In particular, if you have a path in a char const* variable, you must copy the string; e.g.:

char path_copy[PATH_MAX];
strcpy(path_copy, path);
char *argv[] = {path_copy, NULL};
FTS *fts = fts_open(argv, FTS_PHYSICAL, nullptr);

This is using a statically-sized buffer. Depending on your requirements you may want to dynamically allocate a buffer of appropriate size instead.

… it may be possible (likely, even) that fts_open doesn’t actually modify its arguments, so casting away the const instead of copying the string should be possible. But the documentation of fts_open gives no such guarantee, so I advise against it.