basic data structure

First, the integer type:
src/core/ngx_config.h

<code><span>typedef</span> intptr_t        ngx_int_t;
<span>typedef</span> uintptr_t       ngx_uint_t;
<span>typedef</span> intptr_t        ngx_flag_t;</code>

That is, integer, unsigned integer and bool. Three types such as intptr_t are defined as follows:
/usr/local/include/stdint.h

<code><span>/* Types for `void *' pointers.  */</span><span>#if __WORDSIZE == 64</span><span># ifndef __intptr_t_defined</span>
typedef <span>long</span><span>int</span>        intptr_t;
<span>#  define __intptr_t_defined</span><span># endif</span>
typedef unsigned <span>long</span><span>int</span>   uintptr_t;
<span>#else</span><span># ifndef __intptr_t_defined</span>
typedef <span>int</span>         intptr_t;
<span>#  define __intptr_t_defined</span><span># endif</span>
typedef unsigned <span>int</span>        uintptr_t;
<span>#endif</span></code>

That is: 64-bit system uses long integer (8 bytes), otherwise uses integer (4 bytes).

Then the string type:
/src/core/ngx_string.h

<code><span>typedef</span> struct {
    size_t      len;
    u_char     *<span><span>data</span>;</span>
} ngx_str_t;
</code>

Next, a bunch of string-related functions are defined, similar to the member functions corresponding to ngx_str_t.

<code><span>typedef</span><span>struct</span> {
    ngx_str_t   key;
    ngx_str_t   value;
} ngx_keyval_t;


<span>typedef</span><span>struct</span> {  <span>// 位域用来标示类型等元信息</span><span>unsigned</span>    len:<span>28</span>;
    <span>unsigned</span>    valid:<span>1</span>;
    <span>unsigned</span>    no_cacheable:<span>1</span>;
    <span>unsigned</span>    not_found:<span>1</span>;
    <span>unsigned</span>    escape:<span>1</span>;

    u_char     *data;
} ngx_variable_value_t;
<span>typedef</span><span>struct</span> {
    ngx_rbtree_node_t         node;
    ngx_str_t                 str;
} ngx_str_node_t;</code>

The system's errno.h, and the final error number after multi-level include is defined in /usr/include/asm-generic/errno.h. The strerror and strerror_r functions are declared in string.hCopyright statement: This article is an original article by the blogger and may not be reproduced without the blogger's permission.

Function	Description
ngx_string(str)	Constructor, str points to The error number is defined in src/os/unix/ngx_errno.h
The above has introduced the basic data structure, including various aspects. I hope it will be helpful to friends who are interested in PHP tutorials.