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

Bắt đầu bằng cách tái hiện đầu ra cảnh báo với các cờ trình biên dịch được liệt kê, sau đó xem xét các ví dụ trong lib/commonmarker/src/buffer.c, cmark-gfm.h, chunk.h, blocks.c và lib/whereami/whereami.c. Kiểm tra toàn bộ đầu ra của bản build để xác định các cảnh báo còn lại và quyết định cảnh báo nào phù hợp để sửa. Được xem là hoàn tất khi các cảnh báo liên quan đã được xử lý và dự án vẫn build và test thành công.

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)) {