Programming in C

494 Appendix C Compiling Programs with gcc

Command-Line Options

Ta b le C.2 contains a list of common options used for compiling C programs.

Ta ble C.2 Commonly Used gccOptions

Option Meaning Example

--help Displays summary of common gcc --help

command-line options.

-c Does not link the files, saves the gcc –c

object files using .o for the enumerator.c

suffix of each object file.

-dumpversion Displays current version of gcc. gcc -dumpversion

-g Includes debugging information, gcc –g testprog.c

typically for use with gdb(use –o testprog

–ggdbif multiple debuggers are

supported).

-D id In the first case, defines the identifier gcc –D DEBUG=3

-D id=value idto the preprocessor with value 1. test.c

In the second case, defines the identifier

idand sets its value to value.

-E Just preprocesses files and writes results gcc –E

to standard output; useful for examining enumerator.c

the results of preprocessing.

-I dir Adds directory dirto the list of gcc –I /users/

directories to be searched for header steve/include x.c

files; this directory is searched before

other standard directories.

-llibrary Resolves library references against the gcc

file specified by library.This option mathfuncs.c -lm

should be specified after the files that need

functions from the library.The linker

searches standard places (see the –Loption)

for a file named liblibrary.a.

-L dir Adds directory dirto the list of directories gcc –L /users/

to be searched for library files.This directory steve/lib x.c

is searched first before other standard directories.

-o execfile Places the executable file in the file named gcc dbtest.c –o

execfile. dbtest

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