SyntaxFix

[c] How to compile a static library in Linux?

Here a full makefile example:

makefile

TARGET = prog

$(TARGET): main.o lib.a
    gcc $^ -o $@

main.o: main.c
    gcc -c $< -o $@

lib.a: lib1.o lib2.o
    ar rcs $@ $^

lib1.o: lib1.c lib1.h
    gcc -c -o $@ $<

lib2.o: lib2.c lib2.h
    gcc -c -o $@ $<

clean:
    rm -f *.o *.a $(TARGET)

explaining the makefile:

  • target: prerequisites - the rule head
  • $@ - means the target
  • $^ - means all prerequisites
  • $< - means just the first prerequisite
  • ar - a Linux tool to create, modify, and extract from archives see the man pages for further information. The options in this case mean:
    • r - replace files existing inside the archive
    • c - create a archive if not already existent
    • s - create an object-file index into the archive

To conclude: The static library under Linux is nothing more than a archive of object files.

main.c using the lib

#include <stdio.h>

#include "lib.h"

int main ( void )
{
    fun1(10);
    fun2(10);
    return 0;
}

lib.h the libs main header

#ifndef LIB_H_INCLUDED
#define LIB_H_INCLUDED

#include "lib1.h"
#include "lib2.h"

#endif

lib1.c first lib source

#include "lib1.h"

#include <stdio.h>

void fun1 ( int x )
{
    printf("%i\n",x);
}

lib1.h the corresponding header

#ifndef LIB1_H_INCLUDED
#define LIB1_H_INCLUDED

#ifdef __cplusplus
   extern “C” {
#endif

void fun1 ( int x );

#ifdef __cplusplus
   }
#endif

#endif /* LIB1_H_INCLUDED */

lib2.c second lib source

#include "lib2.h"

#include <stdio.h>

void fun2 ( int x )
{
    printf("%i\n",2*x);
}

lib2.h the corresponding header

#ifndef LIB2_H_INCLUDED
#define LIB2_H_INCLUDED

#ifdef __cplusplus
   extern “C” {
#endif

void fun2 ( int x );

#ifdef __cplusplus
   }
#endif

#endif /* LIB2_H_INCLUDED */

Examples related to c

• conflicting types for 'outchar' • Can't compile C program on a Mac after upgrade to Mojave • Program to find largest and second largest number in array • Prime numbers between 1 to 100 in C Programming Language • In c, in bool, true == 1 and false == 0? • How I can print to stderr in C? • Visual Studio Code includePath • "error: assignment to expression with array type error" when I assign a struct field (C) • Compiling an application for use in highly radioactive environments • How can you print multiple variables inside a string using printf?

Examples related to gcc

• Can't compile C program on a Mac after upgrade to Mojave • Compiling an application for use in highly radioactive environments • Make Error 127 when running trying to compile code • How to Install gcc 5.3 with yum on CentOS 7.2? • How does one set up the Visual Studio Code compiler/debugger to GCC? • How do I set up CLion to compile and run? • CMake error at CMakeLists.txt:30 (project): No CMAKE_C_COMPILER could be found • How to printf a 64-bit integer as hex? • Differences between arm64 and aarch64 • Fatal error: iostream: No such file or directory in compiling C program using GCC

Examples related to static-libraries

• "relocation R_X86_64_32S against " linking Error • How do I tell CMake to link in a static library in the source directory? • File is universal (three slices), but it does not contain a(n) ARMv7-s slice error for static libraries on iOS, anyway to bypass? • What's the difference between .so, .la and .a library files? • Telling gcc directly to link a library statically • static linking only some libraries • How to compile a static library in Linux? • Difference between static and shared libraries? • Trying to include a library, but keep getting 'undefined reference to' messages • DLL and LIB files - what and why?