In Linux, the h file is a header file in the system. It is generally used to store some reused code, such as function declarations, variable declarations, constant declarations, macro definitions, etc.; the header file is a After editing the text file with a text editor, save it with the extension ".h".
#The operating environment of this tutorial: linux7.3 system, Dell G3 computer.
What is the h file in Linux
The header file is a text file. After writing the code using a text editor, just save it with the extension .h. Header files generally contain some reused code, such as function declarations, variable declarations, constant definitions, macro definitions, etc.
There are a total of 32 .h header files in the header file directory. Among them, there are 13 in the main directory, 4 in the asm subdirectory, 10 in the Linux subdirectory, and 5 in the sys subdirectory.
: a.out header file, which defines the a.out execution file format and some macros.
: Constant symbol header file, currently only defines the flag bits of the i_mode field in the i node.
: Character type header file, which defines some macros related to character type judgment and conversion.
: Error number header file, containing various error numbers in the system. (Introduced by Linus from minix).
: File control header file, used for the definition of operation control constant symbols for files and their descriptors.
: Signal header file, defining signal symbol constants, signal structures and signal operation function prototypes.
: Standard parameter header file, which defines the variable parameter list in the form of macros. It mainly explains one type (va_list) and three macros (va_start, va_arg and va_end), which are used for vsprintf, vprintf and vfprintf functions.
: Standard definition header file, which defines NULL, offsetof(TYPE, MEMBER).
: String header file, which mainly defines some embedded functions related to string operations.
: Terminal input and output function header file, mainly defines the terminal interface that controls the asynchronous communication port.
: Time type header file, which mainly defines the tm structure and some time-related function prototypes.
: Linux standard header file, which defines various symbolic constants and types, and declares various functions. For example, if __LIBRARY__ is defined, it also includes the system call number and inline assembly _syscall0(), etc.
: User time header file, which defines the access and modification time structure and utime() prototype.
Architecture-related header file subdirectory include/asm
These header files mainly define some data structures, macro functions and variables that are closely related to the CPU architecture. 4 files in total.
: I/O header file, which defines functions for operating I/O ports in the form of macro embedded assembler.
: Memory copy header file, containing memcpy() embedded assembly macro function.
: Segment operation header file, which defines embedded assembly functions related to segment register operations.
: System header file, which defines embedded assembly macros for setting or modifying descriptors/interrupt gates, etc.
Linux kernel-specific header file subdirectory include/linux
: kernel Configure the header file to define keyboard language and hard disk type (HD_TYPE) options.
: Floppy drive header file, containing some definitions of floppy disk controller parameters.
: File system header file, defining the file table structure (file, buffer_head, m_inode, etc.).
: Hard disk parameter header file, which defines access to hard disk register ports, status codes, partition tables and other information.
: The head header file defines the simple structure of the segment descriptor and several selector constants.
: Kernel header file, containing prototype definitions of some commonly used kernel functions.
: Memory management header file, containing page size definition and some page release function prototypes.
: Scheduler header file, which defines the task structure task_struct and the data of initial task 0,
As well as some embedded assembly function macro statements related to descriptor parameter setting and acquisition.
: System call header file, containing 72 system call C function handlers, starting with "sys_".
: tty header file defines parameters and constants related to tty_io and serial communication.
System-specific data structure subdirectory include/sys
: File status header file, containing file or file system status Structure stat{} and constants.
: Defines the running time structure tms and times() function prototype in the process.
: Type header file, which defines basic system data types.
: System name structure header file.
: Waiting call header file, defining system calls wait() and waitpid() and related constant symbols.
Commonly used header files in Linux
Header files defined by POSIX standards
g`"
Dynamic link
Message display structure
## File tree roaming
Code set conversion usage program
Language information constant
Pattern matching function definition
- ## Currency type
## Database operation-
## Polling function
-
Search table
## String operation
- ## System error log record
- User context
## User limit-
##< sys/sem.h> Semaphore
-
Shared storage
## File system information
Time type
Appended date and time Definition
Vector I/O operation
##OPSIX-defined optional header file
## Asynchronous I/O
- ## Message queue
- Thread
## Execution scheduling
Semaphore
The above is the detailed content of What is the h file in linux. For more information, please follow other related articles on the PHP Chinese website!
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
