리눅스 gcc(linux gcc) 1. compile

1. basic compile

1-1 C workflow

1) compile

  source file(.c) + header file(.h) = object file(.o)

  1 source file => 1 object file

2) link object files

3) link with static libraries

4) link with shared libraries

5) execute or debug

1-2 compile command

direct

gcc file.c

result: create a.out

create object file

gcc -c file.c

result: create file.o

gcc -o file file.o

result: create file(executable file)

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2. library

2-1 static lib vs shared lib

	static lib	shared lib
included in:	compile	runtime(when needed)
suffix	.a	.so

executable file size including static lib is bigger than shared lib.

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3. macro

3-1 define macro

able to define undefined macro in source file with,

gcc -DVAR_NAME=VALUE file.c

3-2 conditional compile

make condition for check macro defined in source file with,

#ifdef MACRO
    ...
#endif

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4. add header/lib

4-1 add standard lib

gcc file.c -lname

standard lib is libname.a in /usr/include/

4-2 add user header

gcc -I. file.c

include all header(.h) in current directory

gcc -L. file.c

include all lib(.a or .so) in current directory

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5. create static lib

ar rcv lib_name.a objfile1.o objfile2.o ...

make lib_name.a lib with objfile1.o + objfile2.o + …

* only with obj file

* if command gcc -L. without including header,

ar t lib_name.a

print all obj file in lib_name.a