compile with -ansi -pedantic -Wall switches automatically with gcc
We are required t开发者_如何转开发o compile C source codes using gcc in this manner:
gcc -ansi -pedantic -Wall program.c
I'm wondering how can I 'automate' this so when I enter:
gcc program.c
It will automatically compile with the 3 switches. Is this possible?
You can also use the implicit rules of make, so that you don't have to write a makefile for every program. Make will automatically call the compiler if you say make foo
and there exists a foo.c
file in the current directory. To add flags to this define the variable CFLAGS
in your environment, e.g. in bash add export CFLAGS="-Wall -pedantic -ansi"
to .bashrc
.
If your program depends on multiple files however you'll have to create a makefile, but for C compilation you can get away with just listing dependancies so long as one of them has the same base name as a target.
For example for this makefile:
# Makefile
foo:foo.o bar.o
running make
will execute the commands
gcc $CFLAGS -c -o foo.o foo.c
gcc $CFLAGS -c -o bar.o bar.c
gcc -o foo foo.o bar.o
without you having to add any rules.
To automate the build of any number of build steps / complex parameters, you should use a makefile.
Once you have a makefile you simply need to type: make
alias gcc="gcc -ansi -pedantic -Wall"
But as @Brian said, you really should use a makefile, or better, a build system like CMake or SCons.
A makefile would be the traditional way, especially as part of a larger build process.
If you frequently want to build without a makefile, you could define an alias in your .bashrc
or equivalent: alias gcc=gcc -ansi -pedantic -Wall
.
You can use a shell script that takes some cues by how its called and invokes make
after setting CFLAGS
appropriately for the occasional one-off build.
Lets say you have /usr/bin/compile
, which is a shell script that looks at $0
to see what name actually invoked it. You then make symbolic links to it named pedantic
, fullwarn
, etc.
In the shell script itself, something like:
OLDCFLAGS=$CFLAGS
WHATAMI=$(basename $0)
case "$WHATAMI" in
pedantic)
export CFLAGS="-Wall -pedantic -ansi"
make $@
exit $?
;;
c99)
export CFLAGS="-std=c99 ... ... ..."
....
Then, to compile foo.c with the extra naggy flags:
pedantic foo
This is handy, as I said for one-off builds, e.g trying to compile code that someone posted in a question, or working out how to use a new library, etc.
For anything else, just use a makefile, as others have said.
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