Add additional C flags to your build (improving your code)

首先使用列出的编译器标志复现警告输出，然后检查 lib/commonmarker/src/buffer.c、cmark-gfm.h、chunk.h、blocks.c 和 lib/whereami/whereami.c 中的示例。检查完整的构建输出，以识别剩余的警告，并确定哪些警告适合修复。相关警告得到处理，并且项目仍能成功构建和测试，即表示完成。

Try to build with the following C flags and improve your code:

 -Wall -Wextra -Wconversion -Wcast-align -Wstrict-prototypes -Wuninitialized -Wshadow -Wformat=2 -Werror=incompatible-pointer-types

You will get some nice warnings, function declarations isnt' a prototype, unused-parameters and quite a lot of sign-conversion warnings.

Maybe it's worth looking into those warnings! Those are there for a reason... Those warnings can now be spotted and fixed, improving your code quality.

Small snippet from the output (NOT the full output):

[build] ../lib/commonmarker/src/buffer.c:161:39: note: in expansion of macro ‘MIN’
[build]   161 |   int result = memcmp(a->ptr, b->ptr, MIN(a->size, b->size));
[build]       |                                       ^~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_strchr’:
[build] ../lib/commonmarker/src/buffer.c:173:60: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]   173 |       (unsigned char *)memchr(buf->ptr + pos, c, buf->size - pos);
[build]       |                                                  ~~~~~~~~~~^~~~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_drop’:
[build] ../lib/commonmarker/src/buffer.c:211:42: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]   211 |       memmove(buf->ptr, buf->ptr + n, buf->size);
[build]       |                                       ~~~^~~~~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_rtrim’:
[build] ../lib/commonmarker/src/buffer.c:222:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   222 |     if (!cmark_isspace(buf->ptr[buf->size - 1]))
[build]       |                        ~~~~~~~~^~~~~~~~~~~~~~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_trim’:
[build] ../lib/commonmarker/src/buffer.c:237:49: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   237 |   while (i < buf->size && cmark_isspace(buf->ptr[i]))
[build]       |                                         ~~~~~~~~^~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_normalize_whitespace’:
[build] ../lib/commonmarker/src/buffer.c:252:29: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   252 |     if (cmark_isspace(s->ptr[r])) {
[build]       |                       ~~~~~~^~~
[build] ../lib/commonmarker/src/buffer.c: In function ‘cmark_strbuf_unescape’:
[build] ../lib/commonmarker/src/buffer.c:271:54: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   271 |     if (buf->ptr[r] == '\\' && cmark_ispunct(buf->ptr[r + 1]))
[build]       |                                              ~~~~~~~~^~~~~~~
[build] [41/58  58% :: 0.717] Building C object lib/whereami/CMakeFiles/whereami.dir/whereami.c.o
[build] ../lib/whereami/whereami.c: In function ‘wai_getExecutablePath’:
[build] ../lib/whereami/whereami.c:204:29: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]   204 |       memcpy(out, resolved, length);
[build]       |                             ^~~~~~
[build] ../lib/whereami/whereami.c: In function ‘wai_getModulePath’:
[build] ../lib/whereami/whereami.c:329:35: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]   329 |             memcpy(out, resolved, length);
[build]       |                                   ^~~~~~
[build] [42/58  60% :: 0.731] Building C object lib/commonmarker/src/CMakeFiles/LibCommonMarker.dir/references.c.o
[build] In file included from ../lib/commonmarker/src/references.c:1:
[build] ../lib/commonmarker/src/cmark-gfm.h:114:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
[build]   114 | cmark_mem *cmark_get_default_mem_allocator();
[build]       | ^~~~~~~~~
[build] ../lib/commonmarker/src/cmark-gfm.h:120:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
[build]   120 | cmark_mem *cmark_get_arena_mem_allocator();
[build]       | ^~~~~~~~~
[build] In file included from ../lib/commonmarker/src/map.h:4,
[build]                  from ../lib/commonmarker/src/references.h:4,
[build]                  from ../lib/commonmarker/src/parser.h:5,
[build]                  from ../lib/commonmarker/src/references.c:2:
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_ltrim’:
[build] ../lib/commonmarker/src/chunk.h:32:41: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    32 |   while (c->len && cmark_isspace(c->data[0])) {
[build]       |                                  ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_rtrim’:
[build] ../lib/commonmarker/src/chunk.h:42:31: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    42 |     if (!cmark_isspace(c->data[c->len - 1]))
[build]       |                        ~~~~~~~^~~~~~~~~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_strchr’:
[build] ../lib/commonmarker/src/chunk.h:57:61: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]    57 |       (unsigned char *)memchr(ch->data + offset, c, ch->len - offset);
[build]       |                                                     ~~~~~~~~^~~~~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_to_cstr’:
[build] ../lib/commonmarker/src/chunk.h:68:45: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    68 |   str = (unsigned char *)mem->calloc(c->len + 1, 1);
[build]       |                                      ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h:70:27: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]    70 |     memcpy(str, c->data, c->len);
[build]       |                          ~^~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_set_cstr’:
[build] ../lib/commonmarker/src/chunk.h:88:51: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    88 |     c->data = (unsigned char *)mem->calloc(c->len + 1, 1);
[build]       |                                            ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h:90:33: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    90 |     memcpy(c->data, str, c->len + 1);
[build]       |                          ~~~~~~~^~~
[build] [42/58  62% :: 0.770] Linking C static library lib/whereami/libwhereami.a
[build] [42/58  63% :: 0.884] Building C object lib/commonmarker/src/CMakeFiles/LibCommonMarker.dir/blocks.c.o
[build] In file included from ../lib/commonmarker/src/syntax_extension.h:4,
[build]                  from ../lib/commonmarker/src/blocks.c:13:
[build] ../lib/commonmarker/src/cmark-gfm.h:114:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
[build]   114 | cmark_mem *cmark_get_default_mem_allocator();
[build]       | ^~~~~~~~~
[build] ../lib/commonmarker/src/cmark-gfm.h:120:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
[build]   120 | cmark_mem *cmark_get_arena_mem_allocator();
[build]       | ^~~~~~~~~
[build] In file included from ../lib/commonmarker/src/map.h:4,
[build]                  from ../lib/commonmarker/src/references.h:4,
[build]                  from ../lib/commonmarker/src/parser.h:5,
[build]                  from ../lib/commonmarker/src/blocks.c:15:
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_ltrim’:
[build] ../lib/commonmarker/src/chunk.h:32:41: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    32 |   while (c->len && cmark_isspace(c->data[0])) {
[build]       |                                  ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_rtrim’:
[build] ../lib/commonmarker/src/chunk.h:42:31: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    42 |     if (!cmark_isspace(c->data[c->len - 1]))
[build]       |                        ~~~~~~~^~~~~~~~~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_strchr’:
[build] ../lib/commonmarker/src/chunk.h:57:61: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]    57 |       (unsigned char *)memchr(ch->data + offset, c, ch->len - offset);
[build]       |                                                     ~~~~~~~~^~~~~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_to_cstr’:
[build] ../lib/commonmarker/src/chunk.h:68:45: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    68 |   str = (unsigned char *)mem->calloc(c->len + 1, 1);
[build]       |                                      ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h:70:27: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘bufsize_t’ {aka ‘int’} may change the sign of the result [-Wsign-conversion]
[build]    70 |     memcpy(str, c->data, c->len);
[build]       |                          ~^~~~~
[build] ../lib/commonmarker/src/chunk.h: In function ‘cmark_chunk_set_cstr’:
[build] ../lib/commonmarker/src/chunk.h:88:51: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    88 |     c->data = (unsigned char *)mem->calloc(c->len + 1, 1);
[build]       |                                            ~~~~~~~^~~
[build] ../lib/commonmarker/src/chunk.h:90:33: warning: conversion to ‘size_t’ {aka ‘long unsigned int’} from ‘int’ may change the sign of the result [-Wsign-conversion]
[build]    90 |     memcpy(c->data, str, c->len + 1);
[build]       |                          ~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c: In function ‘S_set_last_line_blank’:
[build] ../lib/commonmarker/src/blocks.c:51:20: warning: conversion from ‘int’ to ‘uint16_t’ {aka ‘short unsigned int’} may change value [-Wconversion]
[build]    51 |     node->flags &= ~CMARK_NODE__LAST_LINE_BLANK;
[build]       |                    ^
[build] ../lib/commonmarker/src/blocks.c: In function ‘remove_trailing_blank_lines’:
[build] ../lib/commonmarker/src/blocks.c:221:54: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   221 |     if (c != ' ' && c != '\t' && !S_is_line_end_char(c))
[build]       |                                                      ^
[build] ../lib/commonmarker/src/blocks.c:233:29: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   233 |     if (!S_is_line_end_char(c))
[build]       |                             ^
[build] ../lib/commonmarker/src/blocks.c: In function ‘finalize’:
[build] ../lib/commonmarker/src/blocks.c:284:15: warning: conversion from ‘int’ to ‘uint16_t’ {aka ‘short unsigned int’} may change value [-Wconversion]
[build]   284 |   b->flags &= ~CMARK_NODE__OPEN;
[build]       |               ^
[build] ../lib/commonmarker/src/blocks.c:324:49: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   324 |         if (S_is_line_end_char(node_content->ptr[pos]))
[build]       |                                ~~~~~~~~~~~~~~~~~^~~~~
[build] ../lib/commonmarker/src/blocks.c: In function ‘parse_list_marker’:
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:555:24: note: in expansion of macro ‘peek_at’
[build]   555 |     if (!cmark_isspace(peek_at(input, pos))) {
[build]       |                        ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:562:32: note: in expansion of macro ‘peek_at’
[build]   562 |       while (S_is_space_or_tab(peek_at(input, i))) {
[build]       |                                ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c:577:28: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   577 |   } else if (cmark_isdigit(c)) {
[build]       |                            ^
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:588:42: note: in expansion of macro ‘peek_at’
[build]   588 |     } while (digits < 9 && cmark_isdigit(peek_at(input, pos)));
[build]       |                                          ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:596:26: note: in expansion of macro ‘peek_at’
[build]   596 |       if (!cmark_isspace(peek_at(input, pos))) {
[build]       |                          ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:602:34: note: in expansion of macro ‘peek_at’
[build]   602 |         while (S_is_space_or_tab(peek_at(input, i))) {
[build]       |                                  ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c:33:32: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]    33 | #define peek_at(i, n) (i)->data[n]
[build]       |                       ~~~~~~~~~^~~
[build] ../lib/commonmarker/src/blocks.c:605:32: note: in expansion of macro ‘peek_at’
[build]   605 |         if (S_is_line_end_char(peek_at(input, i))) {
[build]       |                                ^~~~~~~
[build] ../lib/commonmarker/src/blocks.c: In function ‘S_parser_feed’:
[build] ../lib/commonmarker/src/blocks.c:711:30: warning: conversion to ‘char’ from ‘unsigned char’ may change the sign of the result [-Wsign-conversion]
[build]   711 |       if (S_is_line_end_char(*eol)) {