skrillac skrillac - 1 month ago 20
C Question

Consecutive if statement flow

if (srcbloc == NULL) {
fprintf(stderr, "warning!: memrip source is null!\n");
exit(1);
}
if (destbloc == NULL) {
destbloc = malloc(len);
}
if (srcbloc == destbloc) {
fprintf(stderr, "warning!: srcbloc = destbloc\n");
exit(1);
}
if (offset < 0) {
fprintf(stderr, "warning!: offset = %i\n", offset);
}
if (len < 0) {
fprintf(stderr, "warning!: len = %i\n", len);
}


I am wondering if all of the if statements will be tested when this program is run?

Answer

Given your code

if (srcbloc == NULL) { /* <-- if this block is entered then, */
  fprintf(stderr, "warning!: memrip source is null!\n"); 
  exit(1); /* <-- Program will exit */ 
}
if (destbloc == NULL) {  /* <-- Allocate destbloc of len length. */
  destbloc = malloc(len); 
}
if (srcbloc == destbloc) { /* <-- if this block is entered then, */
  fprintf(stderr, "warning!: srcbloc = destbloc\n"); 
  exit(1); /* <-- Program will exit */ 
}
if (offset < 0) { 
  fprintf(stderr, "warning!: offset = %i\n", offset); 
}
if (len < 0) { 
  fprintf(stderr, "warning!: len = %i\n", len); 
}

So, if (srcbloc == NULL) or (srcbloc == destbloc) the program will warn (and exit). If any of the other tests match the warnings will be printed but the program will continue to process.

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