getDateN() in ncurses version not working correctly

[craftbyte]

If I select WAV file per-call in the ncurses version, the file names have weird beginnings instead of the expected date. Upon further inspection, I discovered that the issue lies in the use of the getDateN() function. Certain compiler will free character arrays in the function epilogue. This causes the returned string to already be nulled instead of containing a date. This can be observed at least on a stock RPi 5 with Raspbian.

To demonstrate this, I made the following example:

char * getDateN(void) {
  #ifdef AERO_BUILD
  char datename[80];
  #else
  char datename[99];
  #endif
  char * curr2;
  struct tm * to;
  time_t t;
  t = time(NULL);
  printf("time: %d\n", t);
  to = localtime( & t);
  printf("localtime: %d\n", to);
  strftime(datename, sizeof(datename), "%Y%m%d", to);
  curr2 = strtok(datename, " ");
  printf("datename: %s\n", datename);
  printf("curr2(%p): %s\n", curr2, curr2);
  return curr2;
}
int main(int argc, char** argv) {
	char* date = getDateN();
	printf("ret: %s (%p)\n", date, date);
	return 0;
}

The output upon executing is as follows:

time: 1713981393
localtime: 203320136
datename: 20240424
curr2(0x7fffd9dfc5a8): 20240424
ret:  (0x7fffd9dfc5a8)

I think we should move the getDateN function to take a char* argument that it fills with the date using strcpy. I also do not understand the use of 80/92 characted long dates, since strftime will always return a string of length 8. The use of strtok is also not needed in my opinion.

For reference: link to code

[lwvmobile]

I'll put it on the to-do list. If you need it done sooner, feel free to make a pull request on the aw_dev branch. Thanks.

[lwvmobile]

On reflection, might be easier to just mirror what is happening in gettime, like this:

char * getDate()
{
  char * curr = (char *) malloc(30);
  time_t t = time(NULL);
  struct tm * ptm = localtime(& t);
  sprintf(
    curr,
    "%04d-%02d-%02d",
    ptm->tm_year+1900,
    ptm->tm_mon+1,
    ptm->tm_mday
  );
  return curr;
}

Not sure what the optimal amount of memory to allocate is for this though.

[craftbyte]

This would be a memory leak, if we dont free the char array.

[lwvmobile]

I made a branch to work on consolidating and fixing all the date and time related b.s., if you want to take a look see, make suggestions, etc.

Also @ilyacodes if you could can you review my work in progress, make sure I'm not being a dumb ass on this.

[ilyacodes]

@lwvmobile Reviewed with a handful of comments on the commit, mostly just nits. Looks sane and nice to have the functionality in one place.

[lwvmobile]

@craftbyte Try pulling and compiling the latest version, see if it fixes your issues on stock RPi 5 with Raspbian.

[lwvmobile]

Going to go ahead and close this as completed now.