Question

I’ve written a .cpp file with a number of functions in it, and now need to declare them in the header file. It occurred to me that I could grep the file for the class name, and get the declarations that way, and it would’ve worked well enough, too, had the complete function declaration before the definition — return code, name, and parameters (but not function body) — been on one line.

It seems to me that this is something that would be generally useful, and must’ve been solved a number of times. I am happy to edit the output and not worried about edge cases; anything that gives me results that are right 95% of the time would be great.

So, if, for example, my .cpp file had:

i2cstatus_t NXTI2CDevice::writeRegisters(
    uint8_t  start_register,    // start of the register range
    uint8_t  bytes_to_write,    // number of bytes to write
    uint8_t* buffer = 0)        // optional user-supplied buffer
{
...
}

and a number of other similar functions, getting this back:

i2cstatus_t NXTI2CDevice::writeRegisters(
        uint8_t  start_register,    // start of the register range
        uint8_t  bytes_to_write,    // number of bytes to write
        uint8_t* buffer = 0)

for inclusion in the header file, after a little editing, would be fine.

Getting this back:

i2cstatus_t writeRegisters(
        uint8_t  start_register,    
        uint8_t  bytes_to_write,    
        uint8_t* buffer);

or this:

i2cstatus_t writeRegisters(uint8_t  start_register, uint8_t  bytes_to_write, uint8_t* buffer);

would be even better.

Answer 1

I compiled exuberant ctags version 5.8. This command gets me what I want:

/usr/local/bin/ctags -x --c-kinds=f $SOURCE |
awk -v OFS=" " '$1=$1' |
cut -d " " -f 5- |
sed -e 's/[A-Za-z]*:://g' |
sed -e 's/)$/);/'

where you substitute the filename you are interested in in place of $SOURCE.

Note that the ctags command by itself gives a reasonable output, and you can throw in a -u flag if you want the output in the order it appears in the file, instead of in alphabetical order.