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sf_mem(3)		    Library Functions Manual		     sf_mem(3)

NAME
       sf_malloc,  sf_calloc,  sf_realloc,  sf_strdup, strndup,	strfunc_ctl --
       string duplication and safe memory allocation.

SYNOPSIS
       #include	<strfunc.h>

       Safe malloc(3) analog:

       void *
       sf_malloc(size_t	size);

       Safe calloc(3) analog:

       void *
       sf_calloc(size_t	number,	size_t size);

       Safe realloc(3) analog:

       void *
       sf_realloc(void *ptr, size_t size);

       Duplicate a specified number of characters from the string:

       char *
       strndup(const char *a, size_t num);

       Safe strdup(3) analog:

       char *
       sf_strdup(const char *a);

       int
       strfunc_ctl(int request,	int *optArg);

DESCRIPTION
       Those functions are used	internally by virtually	all  libstrfunc	 func-
       tions to	manipulate memory. They	are wrappers around the	native library
       calls malloc(3),	calloc(3), realloc(3) and provide additional flexibil-
       ity in those cases when system is low in	memory.

       strndup()  used	to copy	the specified number of	characters to a	newly-
       created buffer.

       sf_strdup(),  sf_malloc()  and  sf_realloc()  are   used	  instead   of
       strdup(3), malloc(3) and	realloc(3) analogs to achieve more control and
       safety when computer becomes low	in memory.

       All  functions are defaulted to call abort(3) upon the unsatisfied mem-
       ory request. This default behavior  can	be  easily  changed  by	 using
       strfunc_ctl() call with SF_SET_MEMORY_FAILURE_BEHAVIOR.

       int strfunc_ctl(int request, int	*optArg) used to change	default	behav-
       iour  of	the previously described functions in cases of resource	short-
       age.

       The request argument can	be the following constant:

	       SF_GET_MEMORY_FAILURE_BEHAVIOR
	       SF_SET_MEMORY_FAILURE_BEHAVIOR
	       SF_GET_MEMORY_FAILURE_TRIES
	       SF_SET_MEMORY_FAILURE_TRIES

       to get or set the memory	allocation behaviour appropriately.  While the
       third and fourth	values are used	to get or specify the number of	 tries
       of  allocating  resources before	falling	into a failure case, the first
       two values can be used to switch	the default behaviour to call abort(3)
       in case of failure.  SF_GET_MEMORY_FAILURE_BEHAVIOR  returns  with  and
       SF_SET_MEMORY_FAILURE_BEHAVIOR accept the following values:

	       SF_ARG_MFB_ABORT	     /*	call abort(3) on failure, the default */
	       SF_ARG_MFB_ENOMEM     /*	return NULL with errno set to ENOMEM */
	       SF_ARG_MFB_TRY_ABORT  /*	try N times before calling abort(3) */
	       SF_ARG_MFB_TRY_ENOMEM /*	do the same before returning an	error */
	       SF_ARG_MFB_TRY_NOFAIL /*	loop indefinitely */

       Again,  virually	 all functions defined in libstrfunc are aware of this
       memory control technique, so, for example, you may  respect  that  some
       strfunc	library	function will not return NULL when you've earlier exe-
       cuted something like

	 int memory_control_type = SF_ARG_MFB_TRY_NOFAIL;
	 strfunc_ctl(SF_SET_MEMORY_FAILURE_BEHAVIOR, &memory_control_type);

SEE ALSO
       strfunc(3), malloc(3).

AUTHORS
       Lev Walkin <vlm@lionet.info>

FreeBSD	Ports 14.quarterly	 May 15, 2001			     sf_mem(3)

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