code / bb

   1 //
   2 // utils.c
   3 // Copyright 2021 Bruce Hill
   4 // Released under the MIT license with the Commons Clause
   5 //
   6 // This file contains implementations of some convenience functions for more
   7 // easily error checking.
   8 //
   9 
  10 #include <err.h>
  11 #include <stdarg.h>
  12 #include <stdlib.h>
  13 
  14 //
  15 // If the given argument is nonnegative, print the error message and exit with
  16 // failure. Otherwise, return the given argument.
  17 //
  18 int check_nonnegative(int negative_err, const char *err_msg, ...) {
  19     if (negative_err < 0) {
  20         va_list args;
  21         va_start(args, err_msg);
  22         verr(EXIT_FAILURE, err_msg, args);
  23         va_end(args);
  24     }
  25     return negative_err;
  26 }
  27 
  28 //
  29 // If the given argument is NULL, print the error message and exit with
  30 // failure. Otherwise return the given argument.
  31 //
  32 void *check_nonnull(void *p, const char *err_msg, ...) {
  33     if (p == NULL) {
  34         va_list args;
  35         va_start(args, err_msg);
  36         verr(EXIT_FAILURE, err_msg, args);
  37         va_end(args);
  38     }
  39     return p;
  40 }
  41 
  42 //
  43 // For a given pointer to a memory-allocated pointer, free its memory and set
  44 // the pointer to NULL. (This is a safer alternative to free() that
  45 // automatically NULLs out the pointer so it can't be used after freeing)
  46 //
  47 void delete(void *p) {
  48     if (*(void **)p != NULL) {
  49         free(*(void **)p);
  50         *(void **)p = NULL;
  51     }
  52 }
  53 
  54 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0