align: Add trivial manpage.

[mLib] / track.h

/* -*-c-*-
 *
 * $Id: track.h,v 1.6 2004/04/08 01:36:13 mdw Exp $
 *
 * Tracing functions for debugging
 *
 * (c) 1998 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#ifndef MLIB_TRACK_H
#define MLIB_TRACK_H

#ifdef __cplusplus
  extern "C" {
#endif

#include <stdlib.h>

/*----- Options and conventions -------------------------------------------*
 *
 * The following macros affect the tracking system:
 *
 * @TRACK_ENABLE@:	Enable tracking of memory allocations
 * @TRACK_BLAME@:	Register my context blocks in allocations
 *
 * The reason there are two switches is simple.  It's often the case that a
 * library routine allocates memory for its client.  Therefore, whether we
 * want to record the library or the client depends on how much we trust
 * the two pieces of software.  Setting @TRACK_ENABLE@ and @TRACK_BLAME@
 * suggests that the current source file might leak memory, so we want its
 * context markers in the list.  Setting @TRACK_ENABLE@ but not
 * @TRACK_BLAME@ suggests that we trust this code, but not the code which
 * calls it, so we want to preserve the caller's context markers.
 *
 * Got it?  Good.
 */

/*----- Type definitions --------------------------------------------------*/

/* --- A context buffer --- */

typedef struct track_ctx {
  struct track_ctx *next;
  const char *s;
} track_ctx;

/*----- Functions provided ------------------------------------------------*/

/* --- @track_level@ --- *
 *
 * Arguments:	@unsigned int l@ = tracing level for allocation messages
 *
 * Returns:	---
 *
 * Use:		Sets the trace level for allocation messages.
 */

extern void track_level(unsigned int /*l*/);

/* --- @track_push@ --- *
 *
 * Arguments:	@track_ctx *ctx@ = context holder to push
 *
 * Returns:	---
 *
 * Use:		Pushes the given context block onto the stack.
 */

extern void track_push(track_ctx */*ctx*/);

/* --- @track_pop@ --- *
 *
 * Arguments:	@track_ctx *ctx@ = context holder to pop
 *
 * Returns:	---
 *
 * Use:		Removes the given context block from the stack.
 */

extern void track_pop(track_ctx */*ctx*/);

/* --- @track_malloc@ --- *
 *
 * Arguments:	@size_t sz@ = size requested
 *
 * Returns:	Pointer to allocated space, or null
 *
 * Use:		Allocates memory, and tracks how much is allocated.
 */

extern void *track_malloc(size_t /*sz*/);

/* --- @track_free@ --- *
 *
 * Arguments:	@void *p@ = pointer to an allocated block
 *
 * Returns:	---
 *
 * Use:		Frees memory, and tracks how much is still allocated.
 */

extern void track_free(void */*p*/);

/* --- @track_realloc@ --- *
 *
 * Arguments:	@void *p@ = pointer to an allocated block
 *		@size_t sz@ = how big it wants to be
 *
 * Returns:	Pointer to the new block.
 *
 * Use:		Reallocates a block, tracking how much memory is still
 *		available.
 */

extern void *track_realloc(void */*p*/, size_t /*sz*/);

/* --- @track_used@ --- *
 *
 * Arguments:	---
 *
 * Returns:	A count of how much memory is used currently.
 *
 * Use:		Returns the amount of memory which the @track_@-functions
 *		above have counted as being currently allocated.
 */

extern unsigned long track_used(void);

/* --- @track_list@ --- *
 *
 * Arguments:	@unsigned int l@ = trace level to use
 *
 * Returns:	---
 *
 * Use:		Traces a dump of the currently known blocks.  Combined with
 *		a verbose dump of allocations and deallocations, and a
 *		good idea of which blocks were allocated where, this can
 *		be useful for locating memory leaks.  It's not exactly a
 *		picnic, though.
 */

extern void track_list(unsigned int l);

/*----- Macro wrappers ----------------------------------------------------*/

/* --- If tracking is to be done, set it up --- */

#ifdef TRACK_ENABLE
#  undef malloc
#  define malloc(sz) track_malloc(sz)
#  undef free
#  define free(p) track_free(p)
#  undef realloc
#  define realloc(p, sz) track_realloc(p, sz)
#endif

/* --- Provide a context for doing track-related things --- */

#ifdef TRACK_ENABLE
#  define TRACK(x) x
#else
#  define TRACK(x)
#endif

/* --- Handle contexts --- */

#if defined(TRACK_ENABLE) && defined(TRACK_BLAME)
#  define TRACK_NCTX(name, string) track_ctx name = { 0, string }
#  define TRACK_NPUSH(name) track_push(name)
#  define TRACK_NPOP(name) track_pop(name)
#  define TRACK_CTX(string) TRACK_NCTX(__track_ctx, string)
#  define TRACK_PUSH TRACK_NPUSH(__track_ctx)
#  define TRACK_POP TRACK_NPOP(__track_ctx)
#else
#  define TRACK_NCTX(name, string)
#  define TRACK_NPUSH(name) ((void)0)
#  define TRACK_NPOP(name) ((void)0)
#  define TRACK_CTX(string)
#  define TRACK_PUSH ((void)0)
#  define TRACK_POP ((void)0)
#endif

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif