VARSYM(2) BSD System Calls Manual VARSYM(2)NAME
varsym_get, varsym_set, varsym_list — variant symlink variables
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
#include <sys/varsym.h>
int
varsym_get(int mask, const char *wild, char *buf, int bufsize);
int
varsym_set(int level, const char *name, const char *data);
int
varsym_list(int level, char *buf, int maxsize, int *marker);
DESCRIPTION
The varsym_get() system call retrieves the value of the first variable
whose left side matches wild and return the value in buf. Bufsize speci‐
fies the length of the buffer and mask can be used to further restrict
the search to variables of certain type. A value of VARSYM_ALL_MASK will
search all variables (see below for other mask definitions).
Varsym_set() sets the variable name of type level to the value pointed to
by data.
The varsym_list() system call fills the buffer buf with variable settings
for the specified level. A maximum of maxsize bytes of settings are
returned and marker is set to the actual number of name/value pairs read,
or -1 if no more remain. Varsym_list() must be called repeatedly until
marker is -1 if all settings are to be retrieved. The format of the buf‐
fer is “\000name\000value\000name\000value...”.
The following varsym levels (and masks) are defined in <sys/varsym.h>:
VARSYM_PROC (VARSYM_PROC_MASK)
Per-process variables.
VARSYM_SYS (VARSYM_SYS_MASK)
System wide variables.
VARSYM_PRISON
Used internally.
RETURN VALUES
The varsym_get() and varsym_set() functions return the value 0 if suc‐
cessful; otherwise the value -1 is returned and the global variable errno
is set to indicate the error.
The varsym_list() function returns the number of bytes read if success‐
ful; otherwise the value -1 is returned and the global variable errno is
set to indicate the error.
ERRORS
The varsym system calls will fail when one of the following occurs:
[EINVAL] An invalid level was specified.
[ENOENT] A variable could not be found.
[EOVERFLOW] Insufficient space for storing variable values was
specified.
SEE ALSOvarsym(1)HISTORY
The varsym system calls first appeared in DragonFly 1.0.
AUTHORS
The varsym system calls were written by Matthew Dillon and this manual
page was written by Sascha Wildner.
BSD February 21, 2008 BSD
