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1404 :: Can a warning be promoted to error to prevent compilation?

• gradha (orginal) [2015-07-04T17:48:24+02:00] view original

  The following example code:

  
  type
    MyEnum* = enum OneValue, AnotherValue, ThirdValue
  
  proc printf(format: cstring) {.header: "<stdio.h>", importc: "printf", varargs.}
  
  proc test() =
    for f in MyEnum: echo f, " ", int(f)
    for g in MyEnum: "int value %d\n".printf(g)
  
  when isMainModule: test()
  Run

  Can be compiled with the following command:

  
  nim c --gc:none -r nogc
  Run

  and will generate the following warnings:

  
  nogc.nim(7, 25) Warning: 'f' uses GC'ed memory [GcMem]
  nogc.nim(7, 36) Warning: 'int(f)' uses GC'ed memory [GcMem]
  Run

  I did take a look at the compiler user guide and saw that warnings can be disabled or enabled. Can warnings be promoted to errors to prevent generation of a binary? Can this be done for all of the warnings or just specific ones?

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• Arrrrrrrrr (orginal) [2015-07-04T18:06:14+02:00] view original

  How does f or g in that context use managed memory?

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• gradha (orginal) [2015-07-04T19:45:49+02:00] view original

  g doesn't use managed memory, neither do f nor int(f). It's passing those values to echo which calls the $ proc on them to build a string, and strings are garbage collected. The C printf version doesn't build strings, so no warning there.

  Well, I'll get going parsing the compiler output.

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• Araq (orginal) [2015-07-04T19:46:29+02:00] view original

  Because echo uses $ which returns a GC'ed string.

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