REALPATH(3) Library Functions Manual REALPATH(3)
realpath -- returns the canonicalized absolute pathname
Standard C Library (libc, -lc)
realpath(const char * restrict pathname, char * restrict resolvedname);
The realpath() function resolves all symbolic links, extra ``/''
characters and references to /./ and /../ in pathname, and copies the
resulting absolute pathname into the memory referenced by resolvedname.
The resolvedname argument must refer to a buffer capable of storing at
least MAXPATHLEN characters.
The realpath() function will resolve both absolute and relative paths and
return the absolute pathname corresponding to pathname.
If resolvednamed is NULL, it will be allocated and the returned pointer
can be deallocated using free(3). The realpath() function returns
resolvedname on success. If an error occurs, realpath() returns NULL,
and resolvedname was not allocated by realpath, it will contain the
pathname which caused the problem.
The function realpath() may fail and set the external variable errno for
any of the errors specified for the library functions chdir(2), close(2),
fchdir(2), lstat(2), malloc(3), open(2), readlink(2) and getcwd(3).
realpath() first appeared in X/Open Portability Guide Issue 4, Version 2
(``XPG4.2'') and is part of IEEE Std 1003.1-2001 (``POSIX.1'').
The realpath() function call first appeared in 4.4BSD. In NetBSD 7.0 the
function was updated to accept a NULL pointer for the resolvedname
This implementation of realpath() differs slightly from the Solaris
implementation. The 4.4BSD version always returns absolute pathnames,
whereas the Solaris implementation will, under certain circumstances,
return a relative resolvedname when given a relative pathname.
NetBSD 6.1.5 June 21, 2012 NetBSD 6.1.5