[Glibc and libc] Both glibc and libc are C function libraries under Linux. libc is the ANSI C library under Linux; glibc is the GUN C library under Linux. What is the difference between ANSI C and GNU C? 

 
 

 

       The ANSI C function library is a basic C language function library, which contains the most basic C language library functions. This library can be divided into 15 parts according to header files, including: 

1. <ctype.h>: Contains the function prototype for testing a characteristic character, and the function prototype for converting upper and lower case letters;
2. <errno.h>: Define the macro used to report the error condition;
3. <float.h>: Contains the system's floating point size limit;
4. <math.h>: Function prototype containing math library functions;
5. <stddef.h>: Contains common function definitions used to perform certain calculations C;
6. <stdio.h>: Contains function prototypes of standard input and output library functions, and the information they use;
7. <stdlib.h>: Contains function prototypes for converting numbers to text and text to numbers, as well as function prototypes for memory allocation, random numbers, and other practical functions;
8. <string.h>: function prototype containing string processing functions;
9. <time.h>: Contains function prototypes and types of time and date operations;
10. <stdarg.h>: Contains function prototypes and macros, and is used to process parameter lists of functions with unknown values ​​and types;
11. <signal.h>: Contains function prototypes and macros, used to process various conditions that may occur during program execution;
12. <setjmp.h>: contains prototypes of functions that can bypass general function calls and return sequences, ie non-local jumps;
13. <locale.h>: Contains function prototypes and other information, so that the program can be modified for the region where it runs.
14. The representation method of the region can enable the computer system to process different data expression conventions, such as the date, time, dollar number and large number in the world;
15. <assert.h>: Contains macros and information, used for diagnosis and help program debugging.

The above library functions are available in various IDEs that support the C language.        The GNU C library is something similar to third-party plug-ins. Since Linux is written in C language, some operations of Linux are implemented in C language. Therefore, GUN organization has developed a C language library so that we can make better use of C language to develop programs based on Linux operating system. 

  However, the current different Linux distributions have different treatments for these two libraries, and some may have been integrated into the same library.  

glibc is the implementation of the C standard library under Linux, namely the GNU C Library. glibc itself is the C standard library of GNU, and later gradually became the standard c library of Linux, and the original standard c library Linux libc under Linux is gradually no longer maintained . The standard c libraries under Linux not only have this one, such as uclibc, klibc, and the Linux libc mentioned above, but glibc is undoubtedly the most used . The .so file of glibc in the / lib directory is libc.so.6.

There are two ways to view the glibc version of the current system: 1. 

2.  


[Glibc and glib]       wrong view: there is a "g" in front of glib, so glib is regarded as the stuff of GNU; at the same time, glibc is regarded as a subset of glib.       In fact, glib and glibc are basically not related, and the only thing they may have in common is that they are all libraries that C programming needs to call. glib is the foundation of the Gtk + library and Gnome. glib can be used on multiple platforms, such as Linux, Unix, Windows, etc. glib provides corresponding replacements for many standard and commonly used C language constructs. 

 

 
 

glib is the basic library of GTK + . It consists of five parts: basic types, support for core applications, practical functions, data types and object systems . You can  download the source code at [ http://www.gtk.org gtk website] . It is a comprehensive and practical lightweight C library , which provides the definition of commonly used data structures in C language, related processing functions, interesting and practical macros, portable packaging and some runtime functions, such as events API loop, threads, dynamic invocation, the target system . GTK + is portable, and of course glib is also portable. You can use it under linux or under windows. Applications written using gLib2.0 (version 2.0 of glib), at should be added to the compile command during compilationpkg-config --cflags --libs glib-2.0 , such as:

gcc  pkg-config --cflags --libs glib-2.0  hello.c -o hello

The most famous use of glib is GNOME.

[Official description]

Glib

GLib is a general-purpose utility library, which provides many useful data types, macros, type conversions, string utilities, file utilities, a main loop abstraction, and so on. It works on many UNIX-like platforms, Windows, OS / 2 and BeOS. GLib is released under the GNU Library General Public License (GNU LGPL).

The general policy of GLib is that all functions are invisibly threadsafe with the exception of data structure manipulation functions, where, if you have two threads manipulating the same data structure, they must use a lock to synchronize their operation.

GLib is the low-level core library that forms the basis for projects such as GTK + and GNOME. It provides data structure handling for C, portability wrappers, and interfaces for such runtime functionality as an event loop, threads, dynamic loading, and an object system. 

Glibc 

Overview: 
Any Unix-like operating system needs a C library: the library which defines the `` system calls '' and other basic facilities such as open, malloc, printf, exit ... 
The GNU C Library is used as the C library in the GNU systems and most systems with the Linux kernel.

Project Goals:  
The GNU C Library is primarily designed to be a portable and high performance C library. It follows all relevant standards including ISO C11 and POSIX.1-2008. It is also internationalized and has one of the most complete internationalization interfaces known.

History: 
The history of Unix and various standards determine much of the interface of the C library. In general the GNU C Library supports the ISO C and POSIX standards. We also try to support the features of popular Unix variants (including BSD and System V ) when those do not conflict with the standards. Different compatibility modes (selectable when you compile an application) allow the peaceful coexistence of compatibility support for different varieties of Unix. 

[Other statements]  

libc is actually a general term. Any content that meets the requirements of the C standard is a libc.
glibc is an implementation of libc by the GNU organization. It is one of the foundations of unix / linux.
Microsoft also has its own libc implementation, called msvcrt.
UClibc is also commonly used in the embedded industry, it is a mini version of libc.

【Yasi】

Libc and glibc are at the same level. They are all C standard implementation libraries and one of the cornerstones of the operating system level.

glib is some utilities written in C, that is, C tool library, and libc / glibc has nothing to do.