Failed to compile urweb.c with gcc 11.1

[apple314159]

Use of the local variable names true and false causes conflict with stdbool.h.
Easiest solution is to rename them _true and _false.

libtool: compile: gcc -DHAVE_CONFIG_H -I. -I../../include/urweb -I./../../include/urweb -Wall -Wunused-parameter -Werror -Wno-format-security -Wno-deprecated-declarations -U_FORTIFY_SOURCE -pthread -march=x86-64 -mtune=generic -O2 -pipe -fno-plt -fexceptions -Wp,-D_FORTIFY_SOURCE=2 -Wformat -Werror=format-security -fstack-clash-protection -fcf-protection -MT urweb.lo -MD -MP -MF .deps/urweb.Tpo -c urweb.c -fPIC -DPIC -o .libs/urweb.o
In file included from /usr/include/unicode/utf8.h:37,
from urweb.c:23:
urweb.c: In function ‘uw_Basis_ensqlBool’:
urweb.c:3092:23: error: expected identifier or ‘(’ before numeric constant
3092 | static uw_Basis_int true = 1;
| ^~~~
urweb.c:3093:23: error: expected identifier or ‘(’ before numeric constant
3093 | static uw_Basis_int false = 0;
| ^~~~~
urweb.c:3096:20: error: lvalue required as unary ‘&’ operand
3096 | return (char *)&false;
| ^
urweb.c:3098:20: error: lvalue required as unary ‘&’ operand
3098 | return (char *)&true;
| ^
In file included from /usr/include/unicode/utf8.h:37,
from urweb.c:23:
urweb.c: In function ‘uw_Basis_stringToBool’:
urweb.c:3196:24: error: expected identifier or ‘(’ before numeric constant
3196 | static uw_Basis_bool true = uw_Basis_True;
| ^~~~
urweb.c:3197:24: error: expected identifier or ‘(’ before numeric constant
3197 | static uw_Basis_bool false = uw_Basis_False;
| ^~~~~
urweb.c:3200:12: error: lvalue required as unary ‘&’ operand
3200 | return &true;
| ^
urweb.c:3202:12: error: lvalue required as unary ‘&’ operand
3202 | return &false;
| ^
urweb.c: In function ‘uw_Basis_ensqlBool’:
urweb.c:3099:1: error: control reaches end of non-void function [-Werror=return-type]
3099 | }
| ^
urweb.c: In function ‘uw_Basis_stringToBool’:
urweb.c:3205:1: error: control reaches end of non-void function [-Werror=return-type]
3205 | }
| ^
cc1: all warnings being treated as errors

[achlipala]

Thanks for catching that! I like your idea for a fix. Since you already have an environment set up to reproduce the issue, would you mind producing a PR that builds with GCC 11.1?

[vmsp]

Same thing is causing issues on macOS 11.6 with Apple Clang 13.0

[mdempsky]

I ran into the same issue trying to build urweb on Fedora 35. I used a similar workaround: renaming the local variables to true_ and false_.