DragonFly On-Line Manual Pages

__REALPATH(2)            DragonFly System Calls Manual           __REALPATH(2)

NAME
     __realpath - resolves the canonicalized absolute pathname

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     int
     __realpath(const char * restrict pathname, char * restrict resolved_path,
         size_t len);

DESCRIPTION
     The __realpath() system call is used to support the libc realpath()
     library call.  It basically does the same thing but with a lower-level
     system-call compatible API.  The system call differs from the libc
     function as follows: It requires that the target buffer and the size of
     the target buffer be supplied, it does not (obviously) allocate a target
     buffer if NULL is supplied, and it returns the string length of the
     target buffer (not including the terminator) or -1.  If a failure occurs,
     the target buffer will not be modified (whereas it is in the libc
     function).

     The system call resolves all symbolic links, extra "/" characters and
     references to /./ and /../ in pathname, and copies the resulting absolute
     pathname into the memory pointed to by resolved_path.  The resolved_path
     argument must point to a buffer capable of storing at least len
     characters, and may not be NULL.

     The __realpath() function will resolve both absolute and relative paths
     and return the absolute pathname corresponding to pathname.  All
     components of pathname must exist when __realpath() is called, and all
     but the last component must name either directories or symlinks pointing
     to the directories.

RETURN VALUES
     The realpath() function returns the string length of the path stored in
     the target buffer, not including the terminator, or -1 on failure.

ERRORS
     The function may fail and set the external variable errno for any of the
     errors specified for the library function realpath(3).

SEE ALSO
     realpath(3)

HISTORY
     The __realpath() function first appeared in DragonFly 5.7.

CAVEATS
     This is the system call version of the libc realpath() function, but is
     not a replacement for the libc function due to necessary API differences.

DragonFly 5.9-DEVELOPMENT      February 2, 2020      DragonFly 5.9-DEVELOPMENT