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--- c_language:overview [2021/03/01 13:12] – utedass
+++ c_language:overview [2022/09/12 00:30] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+====== C Language ======
 ====== Things i should read up on ======
@@ Line 4: / Line 6: @@
   * [[https://en.cppreference.com/w/c/language/eval_order|Evaluation order]]
   * [[http://c-faq.com/index.html|C FAQ]]
+  * [[https://www.agner.org/optimize/calling_conventions.pdf|C++ ABI]] -- Not exclusively for C, but still relevant
+  * [[https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html|Statements and Declarations in Expressions]]
+  * What inline in combination with export and static actually does [[https://stackoverflow.com/questions/6312597/is-inline-without-static-or-extern-ever-useful-in-c99|SO1]], [[https://stackoverflow.com/questions/216510/what-does-extern-inline-do|SO2]], [[https://en.cppreference.com/w/c/language/inline|CPP reference]]
+  * [[http://www.catb.org/esr/structure-packing/]] -- The lost art of structure packing
 [[http://www.underhanded-c.org/|Underhanded C Contest]]
+[[http://uguu.org/sources.html|uguu]] -- Anime ascii art
+====== IOCCC ======
 [[https://www.ioccc.org/|The International Obfuscated C Code Contest]]
+  * [[https://stackoverflow.com/questions/19298778/why-does-the-1987-korn-oneliner-print-unix|Best one-liner 1987]]
+====== 8 phases of translation in C ======
+[[https://stackoverflow.com/questions/1476892/poster-with-the-8-phases-of-translation-in-the-c-language/1479972#1479972|stackoverflow]]
+<code>
+                       ANSI C translation phases
+                       =========================
+          +-------------------------------------------------+
+          | map physical characters to source character set |
+          |     replace line terminators with newlines      |
+          |           decode trigraph sequences             |
+          +-------------------------------------------------+
+                                   |
+                                   V
+               +---------------------------------------+
+               | join lines along trailing backslashes |
+               +---------------------------------------+
+                                   |
+                                   V
+     +-------------------------------------------------------------+
+     | decompose into preprocessing tokens and whitespace/comments |
+     |                      strip comments                         |
+     |                      retain newlines                        |
+     +-------------------------------------------------------------+
+                                   |
+                                   V
+          +------------------------------------------------+
+          | execute preprocessing directives/invoke macros |
+          |              process included files            |
+          +------------------------------------------------+
+                                   |
+                                   V
+   +----------------------------------------------------------------+
+   | decode escape sequences in character constants/string literals |
+   +----------------------------------------------------------------+
+                                   |
+                                   V
+                +--------------------------------------+
+                | concatenate adjacent string literals |
+                +--------------------------------------+
+                                   |
+                                   V
+              +------------------------------------------+
+              | convert preprocessing tokens to C tokens |
+              |       analyze and translate tokens       |
+              +------------------------------------------+
+                                   |
+                                   V
+                    +-----------------------------+
+                    | resolve external references |
+                    |        link libraries       |
+                    |      build program image    |
+                    +-----------------------------+
+</code>
 ====== Right-to-left rule ======
+[[https://stackoverflow.com/questions/8392228/complicated-right-to-left-rule-when-defining-a-variable|SO thread]]
+[[https://www.reddit.com/r/learnprogramming/comments/66a4og/the_rightleft_rule_useful_for_understanding_cc/|Reddit]]
 To decode the expression ''char (*(*x())[5])()''
 <code c>
@@ Line 20: / Line 89: @@
 char (*(*x())[5])() : returning char
 </code>
+====== Pointer vs Array ======
+They are NOT the same, despite what people say!
+<code c>
+// Example of char array vs char pointer
+char *str1 = "Foo"; // Pointer. "Foo" resides in TEXT-section
+char str2[] = "Bar"; // Array. "Bar" resides in RAM, copied to DATA section during C-startup
+str1[2] = 'O'; // Illegal, undefined behaviour
+str2[2] = 'R'; // This is fine, it alters content of RAM
+</code>
 ====== Const ======
@@ Line 27: / Line 109: @@
 const uint8_t *foo; // Same as above.
 uint8_t *const foo; // Constant pointer. Can't change the address it is holding.
+</code>
+====== stdint.h, printf and scanf ======
+''stdint.h'' has definitions of ''uint8_t'' etc.
+''inttypes.h'' has definitions of ''PRIu8'' etc, for use with printf and scanf.
+[[https://en.cppreference.com/w/c/types/integer|This site]] lists all available macros and types.
+<code c>
+#include <stdint.h>
+#include <inttypes.h>
+...
+  printf("Printing a uint8_t: %" PRIu8 " woop woop!", var8bit);
 </code>