1.84.1: compile time warnings about leptonica HOT 3 OPEN

Thank you for looking at this. I am impressed with your command :-)

I happened to go through this list a few days ago. With one notable exception these are not problematic. The unused variables are behind preprocessor walls, so the compiler doesn't see their use. The set but unused variables are mostly there to avoid other warnings about ignoring returned data; many of these variables are called "ignore". The 2 unused functions have been used in the past and can be used for debugging or making some data if necessary.

The misleading indentation is a bug I introduced (an extra ';') while fixing stuff yesterday (!)
It's in a unit (partify) that is not working properly yet, so this isn't important.

Finally, the use after free is an error in gplot.c. It's in a section of code that is only invoked if there is an error opening a stream, which would be very rare. This will be fixed in a day or two.

from leptonica.

Even more warnings are produced with clang and compiler option -Weverything:

  18 [-Waddress-of-packed-member]
  96 [-Watomic-implicit-seq-cst]
  39 [-Wbad-function-cast]
  11 [-Wcast-align]
  31 [-Wcast-qual]
   3 [-Wcomma]
 189 [-Wconditional-uninitialized]
   3 [-Wdeclaration-after-statement]
  18 [-Wdisabled-macro-expansion]
   5 [-Wdocumentation-html]
   4 [-Wdocumentation-unknown-command]
1887 [-Wdocumentation]
2118 [-Wdouble-promotion]
   1 [-Wempty-translation-unit]
 158 [-Wfloat-conversion]
  35 [-Wfloat-equal]
   4 [-Wformat-nonliteral]
   5 [-Wformat-pedantic]
1008 [-Wimplicit-float-conversion]
 554 [-Wimplicit-int-conversion]
   1 [-Wliteral-conversion]
   1 [-Wliteral-range]
   2 [-Wmissing-noreturn]
   2 [-Wmissing-prototypes]
  30 [-Wmissing-variable-declarations]
  11 [-Woverlength-strings]
  46 [-Wpadded]
  11 [-Wshadow]
   1 [-Wshift-sign-overflow]
 165 [-Wshorten-64-to-32]
 171 [-Wsign-compare]
1080 [-Wsign-conversion]
   7 [-Wstrict-prototypes]
   1 [-Wunaligned-access]
  13 [-Wundef]
   9 [-Wunreachable-code-break]
   1 [-Wunreachable-code-return]
   8 [-Wunreachable-code]
  25 [-Wunused-but-set-variable]
   1 [-Wunused-const-variable]
   2 [-Wunused-function]
  33 [-Wunused-macros]
 127 [-Wunused-parameter]
  15 [-Wunused-variable]

Some of them are worth being fixed, for example unnecessary conversions between float and double which cost a little bit of performance.

from leptonica.

That list looks like a warning not to get out of bed in the morning because 1000 bad things could happen. Or even worse, you might waste a year of your life chasing down compiler warnings ;-)

Never thought about overhead from float to double conversion. I have used float wherever possible because it saves storage and it used to be faster. So only used double if the precision was necessary (e.g., representing 32 bit integers, transforms near singularities, hashing functions, etc).

from leptonica.