REALPATH(3) BSD 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 ref-
erenced by resolvedname. The resolvedname argument must refer to a buffer capable of stor-
ing at least MAXPATHLEN characters.
The realpath() function will resolve both absolute and relative paths and return the abso-
lute 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 argument.
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.
BSD June 21, 2012 BSD