gen_bitsize.bash

#!/usr/bin/env bash
#
# This program generates a header file that is needed to figure out number of
# bits in different integer types.
#

header_file=$1
binary=`mktemp`

header_base=`basename "${header_file}"`
compile_guard=`echo "${header_base}" | tr '[:lower:]' '[:upper:]' | tr . _`

cat << EOF | gcc -o $binary -x c -

#include <stdio.h>
#include <limits.h>

#define PRINT_DEF(name, val) printf("#define %s    (%u)\n", #name, val);

int main()
{
    printf("#ifndef %s\n#define %s\n\n",
           "${compile_guard}", "${compile_guard}");

    PRINT_DEF(__CHAR_BITS__, sizeof(char) * CHAR_BIT);
    PRINT_DEF(__SHORT_BITS__, sizeof(short) * CHAR_BIT);
    PRINT_DEF(__INT_BITS__, sizeof(int) * CHAR_BIT);
    PRINT_DEF(__LONG_BITS__, sizeof(long) * CHAR_BIT);
    PRINT_DEF(__FLOAT_BITS__, sizeof(float) * CHAR_BIT);
    PRINT_DEF(__DOUBLE_BITS__, sizeof(double) * CHAR_BIT);
    PRINT_DEF(__LONG_DOUBLE_BITS__, sizeof(long double) * CHAR_BIT);

    printf("\n#endif /* %s */\n", "${compile_guard}");
    return 0;
}

EOF

$binary > $header_file
rm -f $binary