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6272 :: importc/linking problem

• adokitkat (orginal) [2020-04-29T00:47:53+02:00] view original

  Hello, I am trying to import C functions from pcap.h library, however without much success. For now I am just trying to print out a integer return from pcap_findalldevs() funcion. This is the code:

  type
    pcap_if {.importc: "struct pcap_if", header: "<pcap.h>"} = object
      next: ptr pcap_if
      name: cstring
      description: cstring
      flags: uint32
    
    pcap_if_t {.importc: "struct pcap_if_t", header: "<pcap.h>"} = pcap_if
  
  proc pcap_findalldevs(a: ptr ptr pcap_if_t, b:cstring) : cint {.importc, header: "<pcap.h>"}
  
  var dev_list: ptr pcap_if_t
  
  echo pcap_findalldevs(addr(dev_list), nil)
  Run

  Compiled with:

   nim c -r ipk.nim --passL:"-L/usr/include/ -lpcap"
  Run

  But this is the error message I get:

  @mipk.nim.c:(.text+0x278): undefined reference to `pcap_findalldevs'
  collect2: error: ld returned 1 exit status
  Error: execution of an external program failed: 'gcc   -o /root/ipk2/ipk  /root/.cache/nim/ipk_d/stdlib_io.nim.c.o /root/.cache/nim/ipk_d/stdlib_system.nim.c.o /root/.cache/nim/ipk_d/@mipk.nim.c.o    -ldl'
  Run

  Could somebody help me please? It seems like it doesn't want to link properly, although I did also try linking with just

  --clib:pcap and --clib:pcap.h
  Run

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• shashlick (orginal) [2020-04-29T01:00:27+02:00] view original

  
  nim c --passL:"-lpcap" -r ipk.nim
  Run

  Putting flags after -r will pass those values to the compiled binary on execution.

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• adokitkat (orginal) [2020-04-29T01:02:01+02:00] view original

  Thank you :)

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