qsort function import error

[johnz1019]

sparse-merkle-tree/c/ckb_smt.h

Line 102 in 6c3c736

qsort(state->pairs, state->len, sizeof(smt_pair_t), _smt_pair_cmp);

I'm testing the c version smt in ckb vm now, a compile problem blocked me.

c/ckb_smt.h: In function 'smt_state_normalize':
c/ckb_smt.h:104:3: error: implicit declaration of function 'qsort' [-Werror=implicit-function-declaration]
  104 |   qsort(state->pairs, state->len, sizeof(smt_pair_t), _smt_pair_cmp);
      |   ^~~~~

which library can I used to import the qsort function in ckb vm?
qsort(state->pairs, state->len, sizeof(smt_pair_t), _smt_pair_cmp)

[doitian]

It is a function from libc, which is too large for ckb vm. You have to find a libc which you can crop the size, https://github.com/nervosnetwork/ckb-c-stdlib/tree/c056b00fedebff527900586848e2d8fdb53ed317 is a good start.

[XuJiandong]

#include <stdlib.h> before #include <ckb_smt.h> :
https://github.com/nervosnetwork/ckb-c-stdlib/blob/master/libc/stdlib.h