sf_mem(3) BSD 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 behav‐
iour 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
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 str‐
func library function will not return NULL when you've earlier executed
something like
int memory_control_type = SF_ARG_MFB_TRY_NOFAIL;
strfunc_ctl(SF_SET_MEMORY_FAILURE_BEHAVIOR, &memory_control_type);
SEE ALSOstrfunc(3), malloc(3).
AUTHORS
Lev Walkin <vlm@lionet.info>
BSD May 15, 2001 BSD
