Valgrind reporting too many mallocs - c

Question

Consider this code:
int main(int argc, char const *argv[])
{
char *string = NULL;
string = malloc(sizeof(char) * 30);
free(string);
return 0;
}
I malloc a char pointer then I free it after. Now consider the valgrind output:
==58317== Memcheck, a memory error detector
==58317== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==58317== Using Valgrind-3.11.0.SVN and LibVEX; rerun with -h for copyright info
==58317== Command: ./a.out
==58317==
==58317==
==58317== HEAP SUMMARY:
==58317== in use at exit: 34,941 bytes in 424 blocks
==58317== total heap usage: 505 allocs, 81 frees, 41,099 bytes allocated
==58317==
==58317== LEAK SUMMARY:
==58317== definitely lost: 0 bytes in 0 blocks
==58317== indirectly lost: 0 bytes in 0 blocks
==58317== possibly lost: 0 bytes in 0 blocks
==58317== still reachable: 0 bytes in 0 blocks
==58317== suppressed: 34,941 bytes in 424 blocks
==58317==
==58317== For counts of detected and suppressed errors, rerun with: -v
==58317== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
How is it possible to have that many mallocs and frees?
Edit: This is what I get when I run with valgrind --leak-check=yes --gen-suppressions=all ./a.out, I am trying to make a supp file.
==60943== Memcheck, a memory error detector
==60943== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==60943== Using Valgrind-3.11.0.SVN and LibVEX; rerun with -h for copyright info
==60943== Command: ./a.out
==60943==
==60943==
==60943== HEAP SUMMARY:
==60943== in use at exit: 34,941 bytes in 424 blocks
==60943== total heap usage: 505 allocs, 81 frees, 41,099 bytes allocated
==60943==
==60943== LEAK SUMMARY:
==60943== definitely lost: 0 bytes in 0 blocks
==60943== indirectly lost: 0 bytes in 0 blocks
==60943== possibly lost: 0 bytes in 0 blocks
==60943== still reachable: 0 bytes in 0 blocks
==60943== suppressed: 34,941 bytes in 424 blocks
==60943==
==60943== For counts of detected and suppressed errors, rerun with: -v
==60943== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 15 from 15)

Answer 1

Those blocks were allocated (and some of them freed as well) by a system library that was linked into your executable.
Valgrind has a default suppression file that suppresses leaks in system libraries, which is what you can see further in the output :
==58317== suppressed: 34,941 bytes in 424 blocks
If you want more details on what exactly was suppressed, you can use the -v option.