1.Dd May 15, 2001 2.Dt sf_mem 3 3.Os 4.Sh NAME 5.Nm sf_malloc , 6.Nm sf_calloc , 7.Nm sf_realloc , 8.Nm sf_strdup , 9.Nm strndup , 10.Nm strfunc_ctl 11.Nd string duplication and safe memory allocation. 12.Pp 13.Sh SYNOPSIS 14.Fd #include <strfunc.h> 15.Pp 16Safe 17.Xr malloc 3 18analog: 19.Ft void * 20.Fn sf_malloc "size_t size" 21.Pp 22Safe 23.Xr calloc 3 24analog: 25.Ft void * 26.Fn sf_calloc "size_t number" "size_t size" 27.Pp 28Safe 29.Xr realloc 3 30analog: 31.Ft void * 32.Fn sf_realloc "void *ptr" "size_t size" 33.Pp 34Duplicate a specified number of characters from the string: 35.Ft char * 36.Fn strndup "const char *a" "size_t num" 37.Pp 38Safe 39.Xr strdup 3 40analog: 41.Ft char * 42.Fn sf_strdup "const char *a" 43.Pp 44.Ft int 45.Fn strfunc_ctl "int request" "int *optArg" 46.Pp 47.Sh DESCRIPTION 48Those functions are used internally by virtually all 49.Nm libstrfunc 50functions to manipulate memory. They are wrappers around the native 51library calls 52.Xr malloc 3 , 53.Xr calloc 3 , 54.Xr realloc 3 55and provide additional flexibility in those cases when system is low in memory. 56.Pp 57.Fn strndup 58used to copy the specified number of characters to a newly-created buffer. 59.Pp 60.Fn sf_strdup , 61.Fn sf_malloc 62and 63.Fn sf_realloc 64are used instead of 65.Xr strdup 3 , 66.Xr malloc 3 67and 68.Xr realloc 3 69analogs to achieve more control and safety when computer becomes low in memory. 70.Pp 71All functions are defaulted to call 72.Xr abort 3 73upon the unsatisfied memory request. This default behavior can be easily 74changed by using 75.Fn strfunc_ctl 76call with SF_SET_MEMORY_FAILURE_BEHAVIOR. 77.Pp 78.Ft int 79.Fn strfunc_ctl "int request" "int *optArg" 80used to change default behaviour of the previously described functions in 81cases of resource shortage. 82.Pp 83The 84.Em request 85argument can be the following constant: 86.Bd -literal 87 SF_GET_MEMORY_FAILURE_BEHAVIOR 88 SF_SET_MEMORY_FAILURE_BEHAVIOR 89 SF_GET_MEMORY_FAILURE_TRIES 90 SF_SET_MEMORY_FAILURE_TRIES 91.Ed 92.Pp 93to get or set the memory allocation behaviour appropriately. 94While the third and fourth values are used to get or specify the number 95of tries of allocating resources before falling into a failure case, 96the first two values can be used to switch the default behaviour to 97call 98.Xr abort 3 99in case of failure. 100.Em SF_GET_MEMORY_FAILURE_BEHAVIOR 101returns with and 102.Em SF_SET_MEMORY_FAILURE_BEHAVIOR 103accept the following values: 104.Bd -literal 105 SF_ARG_MFB_ABORT /* call abort(3) on failure, the default */ 106 SF_ARG_MFB_ENOMEM /* return NULL with errno set to ENOMEM */ 107 SF_ARG_MFB_TRY_ABORT /* try N times before calling abort(3) */ 108 SF_ARG_MFB_TRY_ENOMEM /* do the same before returning an error */ 109 SF_ARG_MFB_TRY_NOFAIL /* loop indefinitely */ 110.Ed 111.Pp 112Again, virually all functions defined in 113.Nm libstrfunc 114are aware of this memory control technique, so, for example, you may respect 115that some strfunc library function will not return NULL when you've earlier 116executed something like 117.Bd -literal 118 int memory_control_type = SF_ARG_MFB_TRY_NOFAIL; 119 strfunc_ctl(SF_SET_MEMORY_FAILURE_BEHAVIOR, &memory_control_type); 120.Ed 121.Pp 122.Sh SEE ALSO 123.Xr strfunc 3 , 124.Xr malloc 3 . 125.Sh AUTHORS 126.An Lev Walkin <vlm@lionet.info> 127