Sometimes when debugging things like crashes or memory leaks you end up doing a lot of printfs with %p to try to figure what is happening.
There are two common problems with this.
- Pointers are very long hex-strings which are painful to read and compare.
- If you run the same job twice the addresses will be different, so its hard to compare logs.
Enter libuniqueptr.so. If you use this from the app (using e.g. LD_PRELOAD),
then any call to printf() or g_print() will be formated such that the
first ever printed value is 0u1, the second is 0u2, etc, and if these
are ever printed again the same value is used.
For example:
printf ("'%-20p' '%20p' %p\n", &a, &b, &c);
printf ("'%-20p' '%20p' %p\n", &a, &b, &c);
Would normally print:
$ ./testprint
'0x7ffccf56607d ' ' 0x7ffccf56607e' 0x7ffccf56607f
'0x7ffccf56607d ' ' 0x7ffccf56607e' 0x7ffccf56607f
But with libuniqueptr.so:
$ LD_PRELOAD=./libuniqueptr.so ./testprint
'0u1 ' ' 0u2' 0u3
'0u1 ' ' 0u2' 0u3