fix reading of long lines from stdin

[gromgit]

Also refactor slurp_file() in the process.

Addresses #191.

[jpmens]

Looks good to me. Thank you, Adrian!

[1480c1]

This commit causes an error

../jo.c:183:64: error: macro "errx" requires 3 arguments, but only 2 given
  183 |                 errx(1, "Line too large to be read into memory");
      |                                                                ^
../jo.c:51: note: macro "errx" defined here
   51 | # define errx(n, f, a)  { fprintf(stderr, f, a); exit(n); }
      | 
../jo.c:183:17: error: 'errx' undeclared (first use in this function)
  183 |                 errx(1, "Line too large to be read into memory");
      |                 ^~~~

possible fix is to replace errx() with just err() or modify the call to have some argument

[jpmens]

What platform OS/version are you building on? This builds silently for me on Darwin, and Debian11

[1480c1]

Windows 11 with msys2's mingw-w64 gcc and clang compiler, seems I missed a few lines in the error log, so I've added them

[jpmens]

And that macro’s been there since 2016 .. so it’s not this commit.

[1480c1]

As another note, there are a few other warnings

../jo.c:55: warning: "fseeko" redefined
   55 | # define fseeko fseek
      | 
In file included from ../jo.c:3:
D:/media-autobuild_suite/msys64/mingw32/include/stdio.h:672: note: this is the location of the previous definition
  672 | #define fseeko fseeko64
      | 
../jo.c:56: warning: "ftello" redefined
   56 | # define ftello ftell
      | 
D:/media-autobuild_suite/msys64/mingw32/include/stdio.h:679: note: this is the location of the previous definition
  679 | #define ftello ftello64
      | 
../jo.c:65:27: warning: ISO C does not permit named variadic macros [-Wvariadic-macros]
   65 | #define debug(format, args...) fprintf (stderr, format, args)
      |                           ^~~
../jo.c: In function 'slurp_file':
../jo.c:170:22: warning: comparison of unsigned expression in '< 0' is always false [-Wtype-limits]
  170 |         if (*out_len < 0) {
      |                      ^
../jo.c: In function 'slurp_line':
../jo.c:182:22: warning: comparison of unsigned expression in '< 0' is always false [-Wtype-limits]
  182 |         if (*out_len < 0) {
      |                      ^
../jo.c:183:64: error: macro "errx" requires 3 arguments, but only 2 given
  183 |                 errx(1, "Line too large to be read into memory");
      |                                                                ^
../jo.c:51: note: macro "errx" defined here
   51 | # define errx(n, f, a)  { fprintf(stderr, f, a); exit(n); }
      | 
../jo.c:183:17: error: 'errx' undeclared (first use in this function)
  183 |                 errx(1, "Line too large to be read into memory");
      |                 ^~~~
../jo.c:183:17: note: each undeclared identifier is reported only once for each function it appears in
../jo.c: In function 'utf8_from_locale':
../jo.c:548:17: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'unsigned int'} and 'int' [-Wsign-compare]
  548 |         if (len == -1) {
      |                 ^~
../jo.c: In function 'locale_from_utf8':
../jo.c:581:17: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'unsigned int'} and 'int' [-Wsign-compare]
  581 |         if (len == -1) {
      |                 ^~

[1480c1]

669f3fe shows that the instance of errx on line 183 has been added with this pr

[jpmens]

But not its definition at the top of jo.c wrapped in #ifdef.

I’m not in a position to clarify this for that platform now, but if you can and can produce a patch which fixes it, I’d appreciate it.

[1480c1]

https://elixir.bootlin.com/glibc/glibc-2.31/source/misc/err.h#L50

I see why it doesn't care on debian at least, errx there is defined with the third argument as variadic rather than a required argument

I will try to see if I can produce a patch to fix the issue

As another note, I am able to reproduce this with x86_64-w64-mingw32-gcc (gcc 12.2.0 "x86_64-w64-mingw32-gcc (GCC) 12.2.0") provided by archlinux

[1480c1]

Hi @jpmens, I've opened pr #193 to address the warnings and errors that I saw. I did not have a easy fix for the debug macro warning as it seems relatively harmless so long as you are using a gnu standard or some other standard that allows it as an extension