C++ error: no matching function for call to ''"

Question

Although this question has been asked previously on the community, however, those other cases are different from mine, and their solutions cannot be applied in my case.

So I have a very big header "rrc_nbiot.h" file with the following struct:

#include "rrc.h"

namespace asn1 {
namespace rrc {
...
// SystemInformationBlockType2-NB-r13 ::= SEQUENCE
struct sib_type2_nb_r13_s {
  struct freq_info_r13_s_ {
    bool                  ul_carrier_freq_r13_present = false;
    carrier_freq_nb_r13_s ul_carrier_freq_r13;
    uint8_t               add_spec_emission_r13 = 1;
  };
  using multi_band_info_list_r13_l_ = bounded_array<uint8_t, 8>;
  struct freq_info_v1530_s_ {
    tdd_ul_dl_align_offset_nb_r15_e tdd_ul_dl_align_offset_r15;
  };

  // member variables
  bool                          ext                              = false;
  bool                          multi_band_info_list_r13_present = false;
  bool                          late_non_crit_ext_present        = false;
  rr_cfg_common_sib_nb_r13_s    rr_cfg_common_r13;
  ue_timers_and_consts_nb_r13_s ue_timers_and_consts_r13;
  freq_info_r13_s_              freq_info_r13;
  time_align_timer_e            time_align_timer_common_r13;
  multi_band_info_list_r13_l_   multi_band_info_list_r13;
  dyn_octstring                 late_non_crit_ext;
  // ...
  // group 0
  bool cp_reest_r14_present = false;
  // group 1
  bool serving_cell_meas_info_r14_present = false;
  bool cqi_report_r14_present             = false;
  // group 2
  bool                         enhanced_phr_r15_present = false;
  bool                         cp_edt_r15_present       = false;
  bool                         up_edt_r15_present       = false;
  copy_ptr<freq_info_v1530_s_> freq_info_v1530;

  // sequence methods
  SRSASN_CODE pack(bit_ref& bref) const;
  SRSASN_CODE unpack(cbit_ref& bref);
  void        to_json(json_writer& j) const;
};
...
} // namespace rrc
} // namespace asn1

The member function "pack" that is declared in the struct above is defined in another file. "rrc_nbiot.cc"

// SystemInformationBlockType2-NB-r13 ::= SEQUENCE
SRSASN_CODE sib_type2_nb_r13_s::pack(bit_ref& bref) const
{
  /*  some code */
  return SRSASN_SUCCESS;
}

In my main file "main.cpp" I instantiate the struct and try to call the member function as such:

#include "srsran/asn1/rrc_nbiot.h"
struct asn1::rrc::sib_type2_nb_r13_s sib2;
struct asn1::rrc::sib_type2_nb_r13_s *sib2_ref = &sib2;

int main(int argc, char** argv)
{

  uint8_t buf[1024];
  uint32_t nof_bytes = 2;
  asn1::bit_ref  bref;

  sib2_ref->pack(&bref);
...

When I compile, I get the error:

" error: no matching function for call to ‘asn1::rrc::sib_type2_nb_r13_s::pack(asn1::bit_ref*)’
sib2_ref->pack(&bref); "

Although as you see in the header file "pack" is clearly declared under "sib_type2_nb_r13_s". Other members of the struct that are not functions I can access and modify without any problems, but calling the member functions like "pack" is giving me this error.

Any help is appreciated

You're trying to pass a `bit_ref*` to a function that takes a `bit_ref&`, which (fairly obviously) doesn't match. Perhaps you need to read about the differences between pointers and references in your favourite C++ book. — molbdnilo, Jan 05 '22 at 12:42
You're passing a pointer whereas `asn1::rrc::sib_type2_nb_r13_s::pack` accepts a reference. — G.M., Jan 05 '22 at 12:42
Some questions from me : why create sib2 as a global? And why create a pointer to sib2, when you can use sib2 directly? You are adding compleixity where it is not needed. — Pepijn Kramer, Jan 05 '22 at 12:45
@molbdnilo, no I am passing the reference &bref to the function — Abdallah Sheikh, Jan 05 '22 at 12:55
@PepijnKramer, no reason I was just making different attempts to make things work. Nevertheless I tried to access the member function with both, using the instance "sib2", and a pointer to the instance "sib2_ref", both attempts gave the same error. — Abdallah Sheikh, Jan 05 '22 at 12:57
I see :) Usually its best to only put the minimum code here to reproduce the problem. You pass the address of bref, thus a pointer. To pass references to a function you don't have to add the "&" , so the syntex should be : sib2.pack(bref). — Pepijn Kramer, Jan 05 '22 at 13:01
@AbdallahSheikh No, `&bref` is a pointer; it applies the "address-of" operator `&`to `bref`, and the result is a `bit_ref*`. The ampersand, `&`, designates references when it is part of a type, like `bit_ref&`, not when it is part of an expression. This is all covered in detail in [good books](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) — molbdnilo, Jan 05 '22 at 13:05
@molbdnilo, Thanks that resolved the problem. I just thought since the function `pack()` is declared with the argument `bit_ref& bref`, I thought that the ampersand **&** indicated I must pass the address to `bref`, and hence my failed attempts. Now the code compiles — Abdallah Sheikh, Jan 05 '22 at 13:12

score 0 · Accepted Answer · edited Jan 05 '22 at 14:17

0

Thanks to @molbdnilo in the comments, I fixed the error. It was as just as he said.

When I call the member function, I should not pass the argument it as a pointer in my case. The argument should be like this:

  sib2_ref->pack(bref);

edited Jan 05 '22 at 14:17

ouflak

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answered Jan 05 '22 at 13:14

Abdallah Sheikh

26
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C++ error: no matching function for call to ''"

1 Answers1