Script to expand macros from C headers

cmacro.sh

#!/bin/bash

# check usage
if [[ $# -eq 0 ]]; then
    echo "usage: cmacro [headers..] MACRO" >&2
    exit 1
fi

# generate temporary file
f=$(mktemp --suffix=.c)

# add headers
while [[ $# -gt 1 ]]; do
    echo '#include <'"$1"'>' >> "$f"
    shift
done

# add marker
marker="================================================================================"
echo "$marker" >> "$f"

# add macro calls
echo "$1" >> "$f"

# expand macros and strip marker
gcc -P -E "$f" | sed -n -e '/'"$marker"'/,$p' | tail -n+2

# remove temporary file
rm "$f"

usage.sh

$ cmacro sys/mman.h "PROT_READ RPOT_WRITE PROT_EXEC"
0x1 0x2 0x4
$ cmacro unistd.h STDIN_FILENO
0
$ cmacro stdio.h EOF
(-1)

superseded by newer cmacro and cenum gist