The meaning of _t in intptr_t

Question

i want to know what is intptr_t ? what means of (_t) ? is it the first word of (tree) or what?

for example in nginx web server , what is ngx_xx_t (_t) ?

what is diffrent between (ngx_xx_t ) and (ngx_xx_s) ? what is (_t) and (_s) ? (Abbreviation)

Answer 1

Generally, the suffix of _t refers to typedef, and _s to a structure. There is no difference to the compiler, but for the benefit of users reading the code. This was once a common practice to apply such suffixes, but is now discouraged due to conflicts with POSIX & basic human confusion. Other similar discussions

• Standard for typedef'ing
• Naming scheme for typedefs
• What does a type followed by _t (underscore-t) represent?
• struct (C programming language)

Example:

// Discouraged
struct foo_s {
    int bar;
};
typdef struct foo_s foo_t;

// Friendly
typedef struct foo_struct {
    int bar;
} foo_type;