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jakh	Aug 16th, 2007 3:14 PM

warning: assignment from incompatible pointer type warning in a function poiter

hello there,
I am writing a C program in which I need a function pointer to be assigned. The code is as follows

typedef struct nsmail_inputstream {



   void *rock; 

   int (*read) (void *rock, 

            char *buf, unsigned size); 

   void (*rewind) (void *rock);

   void (*close) (void *rock);

} nsmail_inputstream_t; 



int Test_read(void *rock,char *buf, unsigned size)

{

     if(fgets(buf,size,(FILE *)rock) == NULL)

         return -1;

     return strlen(buf);

}



nsmail_inputstream_t l_inputStream;



l_inputStream.read = Test_read;

This end up with the following warnings and I can't figure out why please help me,

warning: assignment from incompatible pointer type

Thanks in advace.
--jakh

Jessehk

Aug 16th, 2007 3:54 PM

Seems to work for me :confused:

#include <stdio.h>

#include <stdlib.h>

#include <string.h>



typedef struct nsmail_inputstream {

    void *rock;

    int (*read)( void *rock, char *buf, unsigned size );

    void (*rewind)( void *rock );

    void (*close)( void *rock );

} nsmail_inputstream_t;



int Test_read( void *rock, char *buf, unsigned size ) {

    if ( fgets( buf, size, (FILE *)rock ) == NULL )

        return -1;

    

    return strlen( buf );

}



int main( void ) {

    nsmail_inputstream_t inputStream;

    inputStream.read = Test_read;

    

    return 0;

}

$ gcc -std=c99 -Wall -Wextra -pedantic example.c -o example

$ ./example

peace_of_mind

Aug 16th, 2007 4:16 PM

jakh, what compiler are you using?

jakh	Aug 16th, 2007 11:32 PM

hi all,
Thanks everybody for quick reply, My compiler is gcc and I used the following options.(I have included the required header files etc..)
gcc -g -Wall test.c

yeah it should work , but I don't know why it gives such warnings.

hey Jessehk,
I copy and paste this code and tried , again it worked fine,

Thank your for your help

niteice

Aug 16th, 2007 11:58 PM

Does Test_read have the same declaration as the function pointer?

jakh	Aug 17th, 2007 12:05 AM

yeah it is ...
please see the above code fragment.
Thank you

--jakh

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