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TYPED_MEM(3)	       FreeBSD Library Functions Manual		  TYPED_MEM(3)

NAME
     typed_mem -- heap memory accounting system

LIBRARY
     PDEL Library (libpdel, -lpdel)

SYNOPSIS
     #include <sys/types.h>
     #include <stdio.h>
     #include <stdarg.h>
     #include <pdel/structs/structs.h>
     #include <pdel/structs/type/array.h>
     #include <pdel/util/typed_mem.h>

     void *
     MALLOC(const char *mtype, size_t size);

     void *
     CALLOC(const char *mtype, size_t number, size_t size);

     void *
     REALLOC(const char	*mtype,	void *mem, size_t size);

     void *
     REALLOCF(const char *mtype, void *mem, size_t size);

     void
     FREE(const	char *mtype, void *mem);

     char *
     STRDUP(const char *mtype, const char *str);

     int
     ASPRINTF(const char *mtype, char **ret, const char	*format, ...);

     int
     VASPRINTF(const char *mtype, char **ret, const char *format, va_list ap);

     int
     typed_mem_enable(void);

     char *
     typed_mem_type(const void *mem, char *typebuf);

     int
     typed_mem_usage(struct typed_mem_stats *stats);

     void
     typed_mem_dump(FILE *fp);

     extern const struct structs_type typed_mem_stats_type;

DESCRIPTION
     The typed_mem library provides accounting and sanity checking for heap-
     allocated memory, configurable at run time.

     If	you're reading this man	page because you need to pass a	variable named
     mtype to a	function where a ``typed_mem(3)	memory type'' is required, but
     you don't want to use or deal with	typed memory in	any way, then just
     pass NULL for mtype and stop reading here.	 Otherwise, read on...

     In	this system, the user code uses	the MALLOC(), CALLOC(),	REALLOC(),
     REALLOCF(), FREE(), STRDUP(), ASPRINTF(), and VASPRINTF() macros as
     replacements for their lowercase standard C library equivalents.  These
     macros take an additional first argument, which is	the memory type	for
     the block of memory.  A memory type is simply an ASCII string (of which
     only the first TYPED_MEM_TYPELEN -	1 characters are significant) contain-
     ing a short, human-readable description of	what the memory	is being used
     for.  Note	it is the contents of the string, not the string pointer
     itself, which defines the type.

     Once typed	memory is enabled (see below), any memory allocated with a
     memory type must be reallocated and/or freed with that same type, other-
     wise the library will immediately abort with an assertion failure.	 Simi-
     larly, invoking REALLOC(),	REALLOCF() or FREE() with a pointer that was
     not returned by one of the	allocation macros will also cause an abort.
     In	addition, FREE() never modifies	the value of errno.

     To	accomodate code	that is	not participating in the typed memory system,
     a NULL type may always be used to indicate	a block	that should not	be
     accounted for.  That is, the NULL memory type just	falls through to the
     existing malloc(3), free(3), etc.	For example, scandir(3)	returns	a
     heap-allocated array namelist which the caller must free.	Instead	of
     calling free(namelist) the	caller may call	FREE(NULL, namelist).  Calling
     FREE() in this case with any type other than NULL would result in an
     assertion failure.	 Similarly, memory allocated with NULL memory type may
     be	freed via the normal free(3).

     Memory allocated by the typed_mem macros is bracketed by guard bytes
     before and	after the returned region.  The	REALLOC(), REALLOCF() and
     FREE() routines detect if the program has modified	these bytes, and they
     generate an assertion failure if so.

     If	a source file consistently uses	the typed memory macros	for all	heap
     memory operations,	then it	may define TYPED_MEM_UNDEFINE_ORIGINALS	before
     including <pdel/util/typed_mem.h>.	 This will cause the lowercase names
     to	be redefined in	such a way that	their use will prevent the source file
     from compiling.  This helps avoid inadvertently mixing the	libc routines
     with typed	memory routines.

     Participation in the typed	memory system is optional and configurable at
     run time.	To enable typed	memory accounting, typed_mem_enable() must be
     called once at program start before any heap allocations are performed.
     This function returns zero	if successful, or else -1 with errno set to
     EALREADY if a typed memory	allocation has already been performed.

     If	typed_mem_enable() is never called, then all of	the above macros
     ignore their type argument	and simply fall	through	to the underlying libc
     routines, therefore having	no effect.  The	program	will behave exactly as
     if	the original functions had been	used, except that there	is one func-
     tion call of overhead for each macro.

     typed_mem_usage() may be called to	get the	current	statistics on memory
     types and usage.  An array	of statistics structures is returned, one for
     each type,	containing the number of blocks	and total bytes	allocated
     under that	type:

	/* Statistics for a single memory type */
	struct typed_mem_typestats {
	    char      type[TYPED_MEM_TYPELEN];	  /* type string + '\0'	*/
	    u_int     allocs;			  /* # blocks alloc'd */
	    u_int     bytes;			  /* # bytes alloc'd */
	};

	/* Variable length array of 'struct typed_mem_typestats' */
	DEFINE_STRUCTS_ARRAY(typed_mem_stats, struct typed_mem_typestats);

     The array is sorted lexicographically by type name.  The array itself
     must be eventually	freed by the caller, by	invoking:

	structs_free(&typed_mem_stats_type, NULL, stats);

     typed_mem_usage() returns zero if successful, or else -1 and sets errno
     if	there was an error; in particular, ENXIO if typed memory is not
     enabled.

     A structs(3) type typed_mem_stats_type describing a struct
     typed_mem_stats is	pre-defined.

     typed_mem_type() retrieves	the type for the memory	block pointed to by
     mem and writes it (including terminating '\0') into the buffer pointed to
     by	typebuf, which must have size at least TYPED_MEM_TYPELEN.  If success-
     ful, typed_mem_type() returns typebuf; otherwise typed_mem_type() returns
     NULL.  This will happen if	typed_mem_enable() has not been	called,	if mem
     was allocated with	type NULL, or if mem was never returned	by any of
     these allocation routines.

     typed_mem_dump() prints out the current statistics	on memory types	and
     usage to the supplied output stream.

     The typed_mem routines may	safely be called from multiple threads simul-
     taneously.

SEE ALSO
     assert(3),	libpdel(3), malloc(3), printf(3), structs(3),
     structs_type_array(3)

HISTORY
     The PDEL library was developed at Packet Design, LLC.
     http://www.packetdesign.com/

AUTHORS
     Archie Cobbs <archie@freebsd.org>

FreeBSD	10.3			April 22, 2002			  FreeBSD 10.3

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS

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