Return to tinfo.3 CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / libpdel / util

libpdel

    1: .\" Copyright (c) 2001-2002 Packet Design, LLC.
    2: .\" All rights reserved.
    3: .\" 
    4: .\" Subject to the following obligations and disclaimer of warranty,
    5: .\" use and redistribution of this software, in source or object code
    6: .\" forms, with or without modifications are expressly permitted by
    7: .\" Packet Design; provided, however, that:
    8: .\" 
    9: .\"    (i)  Any and all reproductions of the source or object code
   10: .\"         must include the copyright notice above and the following
   11: .\"         disclaimer of warranties; and
   12: .\"    (ii) No rights are granted, in any manner or form, to use
   13: .\"         Packet Design trademarks, including the mark "PACKET DESIGN"
   14: .\"         on advertising, endorsements, or otherwise except as such
   15: .\"         appears in the above copyright notice or in the software.
   16: .\" 
   17: .\" THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
   18: .\" TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
   19: .\" REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
   20: .\" THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
   21: .\" WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
   22: .\" OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
   23: .\" OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
   24: .\" OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
   25: .\" RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
   26: .\" LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
   27: .\" OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
   28: .\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
   29: .\" DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
   30: .\" USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
   31: .\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   32: .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
   33: .\" THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
   34: .\" THE POSSIBILITY OF SUCH DAMAGE.
   35: .\"
   36: .\" Author: Archie Cobbs <archie@freebsd.org>
   37: .\"
   38: .\" $Id: tinfo.3,v 1.1.1.1 2012/02/21 23:25:53 misho Exp $
   39: .\"
   40: .Dd April 22, 2002
   41: .Dt TINFO 3
   42: .Os
   43: .Sh NAME
   44: .Nm tinfo
   45: .Nd self-(de)allocating thread-local data structures
   46: .Sh LIBRARY
   47: PDEL Library (libpdel, \-lpdel)
   48: .Sh SYNOPSIS
   49: .In pthread.h
   50: .In pdel/util/tinfo.h
   51: .Fn TINFO_INIT type mtype initfunc
   52: .Ft "void *"
   53: .Fn tinfo_get "struct tinfo *t"
   54: .Ft "int"
   55: .Fn tinfo_set "struct tinfo *t" "const void *data"
   56: .Ft "int"
   57: .Fn tinfo_set_nocopy "struct tinfo *t" "void *data"
   58: .Sh DESCRIPTION
   59: These functions provide support for thread-local data structures defined by
   60: .Xr structs 3
   61: types that are automatically initialized and destroyed.
   62: A thread-local data structure is described by a static or global
   63: .Li "struct tinfo" ;
   64: each such structure must be initialized with the
   65: .Fn TINFO_INIT
   66: macro.
   67: For example:
   68: .Pp
   69: .Bd -literal -compact -offset 3n
   70: static struct tinfo foo_info
   71:         = TINFO_INIT(&foo_type, "foo", fooinit);
   72: .Ed
   73: .Pp
   74: .Fa type
   75: is the
   76: .Xr structs 3
   77: type for the data structure,
   78: .Fa mtype
   79: is the
   80: .Xr typed_mem 3
   81: type used to allocate memory to hold each thread's instance, and
   82: .Fa initfunc
   83: is an optional instance initializer function of this type:
   84: .Pp
   85: .Bd -literal -compact -offset 3n
   86: typedef int tinfo_init_t(struct tinfo *t, void *data);
   87: .Ed
   88: .Pp
   89: .Fn initfunc
   90: should initialize the data structure pointed to by
   91: .Fa data
   92: as an instance of
   93: .Fa type
   94: (which will also be available as
   95: .Fa "t->type") .
   96: The memory pointed to by
   97: .Fa data
   98: will have been allocated with
   99: .Xr typed_mem 3
  100: type
  101: .Fa mtype
  102: but will be otherwise uninitialized.
  103: If
  104: .Fa initfunc
  105: is
  106: .Dv NULL ,
  107: then
  108: .Xr structs_init 3
  109: is used to initialize the data structure to the default value defined by
  110: .Fa type .
  111: .Pp
  112: Instances of
  113: .Nm tinfo
  114: thread-local data structure are automatically destroyed when the associated
  115: thread exits, by calling
  116: .Fn structs_free type NULL data
  117: and then
  118: .Fn FREE mtype data .
  119: .Pp
  120: .Fn tinfo_get
  121: returns the current thread's instance of the data structure.
  122: If this is the thread's first invocation of
  123: .Fn tinfo_get ,
  124: a new instance is automatically allocated and initialized.
  125: The caller should
  126: .En not
  127: free the returned value, but may modify it in a way consistent
  128: with its
  129: .Xr structs 3
  130: type.
  131: .Pp
  132: .Fn tinfo_set
  133: sets the current thread's data structure instance to be a copy of
  134: .Fa data ,
  135: made using
  136: .Xr structs_get 3 .
  137: The original
  138: .Fa data
  139: is unmodified and remains the caller's responsibility to free.
  140: Any existing thread-local data structure instance is automatically
  141: replaced and freed.
  142: .Pp
  143: .Fn tinfo_set_nocopy
  144: is equivalent to
  145: .Fn tinfo_set
  146: except that no copy of
  147: .Fa data
  148: is made; therefore,
  149: .Fa data
  150: must point to heap memory allocated with
  151: .Xr typed_mem 3
  152: type
  153: .Fa "mtype"
  154: (also available as
  155: .Fa "t->mtype")
  156: and the caller should not dereference
  157: .Fa data
  158: once
  159: .Fn tinfo_set_nocopy
  160: has returned successfully.
  161: .Pp
  162: Both
  163: .Fn tinfo_set
  164: and
  165: .Fn tinfo_set_nocopy
  166: may take a
  167: .Dv NULL
  168: .Fa data
  169: parameter; this causes any existing thread-local data structure instance
  170: to be freed so that the next call to
  171: .Fn tinfo_get
  172: will cause a new instance to be constructed.
  173: .Sh RETURN VALUES
  174: .Fn tinfo_get ,
  175: .Fn tinfo_set ,
  176: and
  177: .Fn tinfo_set_nocopy
  178: return
  179: .Dv NULL
  180: or -1 with
  181: .Va errno
  182: set appropriately to indicate an error.
  183: .Sh SEE ALSO
  184: .Xr libpdel 3 ,
  185: .Xr structs 3 ,
  186: .Xr typed_mem 3
  187: .Sh HISTORY
  188: The PDEL library was developed at Packet Design, LLC.
  189: .Dv "http://www.packetdesign.com/"
  190: .Sh AUTHORS
  191: .An Archie Cobbs Aq archie@freebsd.org