CODEWITHSUNDEEP
clinuxgcc
KNV Srinivas
KNV Srinivas

Reputation: 61

Use of -g and -o options in gcc command in c programming

Suppose there are 2 c program named abc.c and xyz.c . Now we want to work with the 2 executables at a time. So we change the name of the ./a.out using

gcc -g abc.c -o abc
gcc -g xyz.c -o xyz

Even gcc -o abc abc.c works. What does the -g and -o in the above commands specify or describe? What is the significance of -g and -o in the command for renaming ./a.out file. Thanks in advance.

Upvotes: 2

Views: 5312

Answers (4)

kadina
kadina

Reputation: 5376

if we specify -g option while compiling, debugging symbols will be available in the output file which will be useful when you try to debug using GDB.

If we won't specify -o option, the output will be placed in default a.out file. So if we run

gcc a.c - output will be in a.out
gcc b.c - output is a.out which is replacing old a.out file

If you want the output not to be a.out file, you can give -o option while compiling

gcc abc.c -o a

-o and -g options are not related.

Upvotes: 0

Clusty
Clusty

Reputation: 117

-g starts becoming useful once you use debuggers such as gdb and lldb. When you attach to a running program and advancing one line at a time printing/altering the state as it changes.

Upvotes: 0

Barmar
Barmar

Reputation: 780889

-g means to leave debugging information in the output file, it's unrelated to renaming.

-o means to put the result in the specified file instead of the default filename (abc.o for object files, a.out for linked executable files).

Upvotes: 2

Fred Larson
Fred Larson

Reputation: 62063

From https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html:

-g
    Produce debugging information in the operating system's native format (stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging information.

-o file
    Place output in file file. This applies to whatever sort of output is being produced, whether it be an executable file, an object file, an assembler file or preprocessed C code.

Upvotes: 1

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