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Re: int(*const parse_packet)(const char *, size_t, char **);

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"hongy...@gmail.com" <hongyi.zhao@gmail.com> writes:
> On Tuesday, August 31, 2021 at 7:00:07 PM UTC+8, Bonita Montero wrote:
>> Am 31.08.2021 um 12:35 schrieb hongy...@gmail.com: 
>> > See the following c code snippet located at here [1]: 
>> > 
>> > typedef struct protocol { 
>> > const int default_port; 
>> > int(*const parse_packet)(const char *, size_t, char **); 
>> > } protocol_t; 
>> > 
>> > In the above definition, it seems to me that the `int ...' line is difficult to understand. Any hints will be highly appreciated. 
>> > 
>> > [1] https://github.com/hongyi-zhao/shadowsocksr-libev/blob/1be671bd5fe7cd55d3823d4669786c9ba7913b9e/src/protocol.h#L29
>> That's just a pointer to a function that gets a const char *, a size_t 
>> and a char ** and returns an int; you could assign a function-"name" to 
>> it that returns an int and takes the same parameters in the same order. 
>> For the above definition the parameters don't need to be named since 
>> this isn't a function-definition, but just a variable-definition.
>
> Do you mean this is something similar to lambda discussed here [1]?
>
> [1] https://stackoverflow.com/questions/41700729/how-can-this-c-code-have-lambda

It has some similarities to lambdas, but C doesn't have lambdas.  It's
best just to think of it as a function pointer (and learn what C
function pointers are if you don't already know).

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */

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int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-08-31 03:35 -0700
  Re: int(*const parse_packet)(const char *, size_t, char **); Bonita Montero <Bonita.Montero@gmail.com> - 2021-08-31 12:59 +0200
    Re: int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-08-31 06:07 -0700
      Re: int(*const parse_packet)(const char *, size_t, char **); Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-08-31 08:01 -0700
  Re: int(*const parse_packet)(const char *, size_t, char **); Manfred <noname@add.invalid> - 2021-08-31 15:01 +0200
  Re: int(*const parse_packet)(const char *, size_t, char **); John Bode <jfbode1029@gmail.com> - 2021-08-31 16:08 -0500
    Re: int(*const parse_packet)(const char *, size_t, char **); "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-08-31 14:32 -0700
      Re: int(*const parse_packet)(const char *, size_t, char **); Bart <bc@freeuk.com> - 2021-08-31 22:39 +0100
        Re: int(*const parse_packet)(const char *, size_t, char **); "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-09-01 14:40 -0700
    Re: int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-08-31 18:21 -0700
      Re: int(*const parse_packet)(const char *, size_t, char **); Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-08-31 19:54 -0700
    Re: int(*const parse_packet)(const char *, size_t, char **); Kaz Kylheku <563-365-8930@kylheku.com> - 2021-09-01 05:07 +0000
      Re: int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-08-31 23:19 -0700
  Re: int(*const parse_packet)(const char *, size_t, char **); James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-09-01 10:34 -0400
    Re: int(*const parse_packet)(const char *, size_t, char **); Bart <bc@freeuk.com> - 2021-09-01 16:22 +0100
      Re: int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-09-01 20:02 -0700
        Re: int(*const parse_packet)(const char *, size_t, char **); Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-09-01 21:01 -0700
          Re: int(*const parse_packet)(const char *, size_t, char **); "hongy...@gmail.com" <hongyi.zhao@gmail.com> - 2021-09-01 23:18 -0700
          Re: int(*const parse_packet)(const char *, size_t, char **); scott@slp53.sl.home (Scott Lurndal) - 2021-09-02 15:02 +0000
            Re: int(*const parse_packet)(const char *, size_t, char **); Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2021-09-02 15:24 +0000
        Re: int(*const parse_packet)(const char *, size_t, char **); Bart <bc@freeuk.com> - 2021-09-02 10:40 +0100
  Re: int(*const parse_packet)(const char *, size_t, char **); Paul N <gw7rib@aol.com> - 2021-09-01 08:32 -0700

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