#include <unistd.h> int resolvepath(const char *path, char *buf, size_t bufsiz);
The resolvepath() function fully resolves all symbolic links in the path name path into a resulting path name free of symbolic links and places the resulting path name in the buffer buf which has size bufsiz. The resulting path name names the same file or directory as the original path name. All ``.'' components are eliminated and every non-leading ``..'' component is eliminated together with its preceding directory component. If leading ``..'' components reach to the root directory, they are replaced by ``/''. If the number of bytes in the resulting path name is less than bufsiz, the contents of the remainder of buf are unspecified.
Upon successful completion, resolvepath() returns the count of bytes placed in the buffer. Otherwise, it returns −1, leaves the buffer unchanged, and sets errno to indicate the error.
The resolvepath() function will fail if:
Search permission is denied for a component of the path prefix of path or for a path prefix component resulting from the resolution of a symbolic link.
The path or buf argument points to an illegal address.
An I/O error occurred while reading from the file system.
The path argument is an empty string or a component of path or a path name component produced by resolving a symbolic link does not name an existing file.
Too many symbolic links were encountered in resolving path.
The length of path exceeds PATH_MAX, or a path name component is longer than NAME_MAX. Path name resolution of a symbolic link produced an intermediate result whose length exceeds PATH_MAX or a component whose length exceeds NAME_MAX.
A component of the path prefix of path or of a path prefix component resulting from the resolution of a symbolic link is not a directory.
No more than PATH_MAX bytes will be placed in the buffer. Applications should not assume that the returned contents of the buffer are null-terminated.