1. Create a header file includes the function description, function declaration. for example:
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patrick@debian:~/test/libtest$ vi test_lib.h
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In the test_lib.h, the following information may be added.
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#ifndef __TEST_LIB_H__
#define __TEST_LIB_H__
/* print the "hello world" information */
void print_hello( void );
#endif
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2. Create a implementation file includes the function description and function implementation. for example:
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patrick@debian:~/test/libtest$ vi test_lib.c
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In the file, added the following codes.
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#include <stdio.h>
#include "test_lib.h"
void print_hello( void )
{
printf( "Hello World!\n" );
}
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3. Compile the file to the shared library file.
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gcc -Wall -shared -o libtest_lib.so test_lib.c
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4. View the shared library file.
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patrick@debian:~/test/libtest$ file libtest_lib.so
libtest_lib.so: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), not stripped
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5. Create a test file to test the library function.
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patrick@debian:~/test/libtest$ vi test_main.c
|
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#include <stdio.h>
#include "test_lib.h"
int main(int argc, char *argv[])
{
print_hello();
return 0;
}
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6. Compile the test code file.
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gcc -Wall -o test_main test_main.c -ltest_lib -L.
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7. Modefied the environment variable so that the library can be found.
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export LD_LIBRARY_PATH=.:$LD_LIBRARY_PATH
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8. run the programme.
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patrick@debian:~/test/libtest$ ./test_main
Hello World!
patrick@debian:~/test/libtest$
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