Implicit declaration of function

This is a discussion on Implicit declaration of function within the C Programming forums, part of the General Programming Boards category; Hi, i've done some search in this forum but didn't find any solution. Basically, my program use some functions like: ...

  1. #1
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    Implicit declaration of function

    Hi,
    i've done some search in this forum but didn't find any solution.
    Basically, my program use some functions like: strcpy, strlen ...

    When compiling, it throws some warnings:

    server.c:114: warning: implicit declaration of function `strstr'
    server.c:117: warning: implicit declaration of function `strncpy'
    server.c:125: warning: implicit declaration of function `strlen'
    ....
    .....

    How do i get rid of it (not by using tag while compiling) ? Do i need to #define or #include any extra thing ?

  2. #2
    ex-DECcie
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    Sounds like you need to include string.h

    Code:
    #include <string.h>
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  3. #3
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    i did include both <string.h> and <strings.h>
    But still no help !

    Anh

  4. #4
    Devil's Advocate SlyMaelstrom's Avatar
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    Post your code and what compiler you're using.
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  5. #5
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    Here's the begining of the source code (all include and define):

    Code:
    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <netdb.h> 
    #include <ctype.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>
    #include <strings.h>
    
    #define BUFFERLENGTH 256
    #define _GNU_SOURCE


    And im using
    Code:
     cc -Wall -o
    to compile and generate binary

  6. #6
    Frequently Quite Prolix dwks's Avatar
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    Code:
    server.c:114: warning: implicit declaration of function `strstr'
    server.c:117: warning: implicit declaration of function `strncpy'
    server.c:125: warning: implicit declaration of function `strlen'
    Those functions are all in <string.h>. They are ANSI functions and shouldn't be affected by #defines or compiler switches.

    Try a simple program that uses strlen(), with and without <string.h> included.

    If that doesn't work, maybe you should post more of your code.
    dwk

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