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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 functions
     to manipulate memory. They are wrappers around  the  native  library  calls
     malloc(3),  calloc(3),  realloc(3)  and  provide  additional flexibility in
     those cases when system is low in memory.

     strndup() used to copy the specified number of characters to  a  newly-cre-
     ated 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 memory
     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  behaviour
     of the previously described functions in cases of resource shortage.

     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 val-
     ues 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  mem-
     ory  control  technique, so, for example, you may respect that some strfunc
     library function will not return NULL when you've	earlier  executed  some-
     thing 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 15.quarterly	  May 15, 2001			       sf_mem(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=strndup&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>

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