Question

我正在尝试将这些文件包含在我的主要C代码中：

who.c：

/* who3.c - who with buffered reads
 *    - surpresses empty records
 *    - formats time nicely
 *    - buffers input (using utmplib)
 */
#include    <stdio.h>
#include    <stdlib.h>
#include    <sys/types.h>
#include    <utmp.h>
#include    <fcntl.h>
#include    <time.h>
#include    "utmplib.h"

#define SHOWHOST

void show_info(struct utmp *);
void showtime(time_t);

int Who()
{
    struct utmp *utbufp,    /* holds pointer to next rec    */
            *utmp_next();   /* returns pointer to next  */

    if ( utmp_open( UTMP_FILE ) == -1 ){
        perror(UTMP_FILE);
        exit(1);
    }
    while ( ( utbufp = utmp_next() ) != ((struct utmp *) NULL) )
        show_info( utbufp );
    utmp_close( );
    return 0;
}
/*
 *  show info()
 *          displays the contents of the utmp struct
 *          in human readable form
 *          * displays nothing if record has no user name
 */
void show_info( struct utmp *utbufp )
{

    printf("%-8.8s", utbufp->ut_name);      /* the logname  */
    printf(" ");                    /* a space  */
    printf("%-8.8s", utbufp->ut_line);      /* the tty  */
    printf(" ");                    /* a space  */
    showtime( utbufp->ut_time );            /* display time */
#ifdef SHOWHOST
    if ( utbufp->ut_host[0] != '\0' )
        printf(" (%s)", utbufp->ut_host);   /* the host */
#endif
    printf("\n");                   /* newline  */
}

void showtime( time_t timeval )
/*
 *  displays time in a format fit for human consumption
 *  uses ctime to build a string then picks parts out of it
 *      Note: %12.12s prints a string 12 chars wide and LIMITS
 *      it to 12chars.
 */
{
    char    *ctime();       /* convert long to ascii    */
    char    *cp;            /* to hold address of time  */

    cp = ctime( &timeval );     /* convert time to string   */
                    /* string looks like        */
                    /* Mon Feb  4 00:46:40 EST 1991 */
                    /* 0123456789012345.        */
    printf("%12.12s", cp+4 );   /* pick 12 chars from pos 4 */
}

who.h：

#ifndef WHO_H
#define WHO_H

/* This file was automatically generated.  Do not edit! */
int Who();
void showtime(time_t);
void showtime(time_t timeval);
void show_info(struct utmp *);
void show_info(struct utmp *utbufp);

#endif

utmplib.c：

/* utmplib.c  - functions to buffer reads from utmp file 
 *
 *      functions are
 *              utmp_open( filename )   - open file
 *                      returns -1 on error
 *              utmp_next( )            - return pointer to next struct
 *                      returns NULL on eof
 *              utmp_close()            - close file
 *
 *      reads NRECS per read and then doles them out from the buffer
 */
#include        <stdio.h>
#include        <fcntl.h>
#include        <sys/types.h>
#include        <utmp.h>

#define NRECS   1
#define NULLUT  ((struct utmp *)NULL)
#define UTSIZE  (sizeof(struct utmp))

static  char    utmpbuf[NRECS * UTSIZE];                /* storage      */
static  int     num_recs;                               /* num stored   */
static  int     cur_rec;                                /* next to go   */
static  int     fd_utmp = -1;                           /* read from    */

utmp_open( char *filename )
{
        fd_utmp = open( filename, O_RDONLY );           /* open it      */
        cur_rec = num_recs = 0;                         /* no recs yet  */
        return fd_utmp;                                 /* report       */
}

struct utmp *utmp_next()
{
        struct utmp *recp;
        //struct utmp *nextRecp;
        int match = 0;
        if(recp->ut_type == USER_PROCESS)
        {
            recp = ( struct utmp *) &utmpbuf[cur_rec * UTSIZE];
        }

        while(recp->ut_type!= USER_PROCESS)
        {


        if ( fd_utmp == -1 )                            /* error ?      */
                return NULLUT;
        if ( cur_rec==num_recs && utmp_reload()==0 )    /* any more ?   */
                return NULLUT;
                                        /* get address of next record    */

        recp = ( struct utmp *) &utmpbuf[cur_rec * UTSIZE];
        cur_rec++;
        }

        return recp;





}

int utmp_reload()
/*
 *      read next bunch of records into buffer
 */
{
        int     amt_read;

                                                /* read them in         */
        amt_read = read( fd_utmp , utmpbuf, NRECS * UTSIZE );   

                                                /* how many did we get? */
        num_recs = amt_read/UTSIZE;
                                                /* reset pointer        */
        cur_rec  = 0;
        return num_recs;
}

utmp_close()
{
        if ( fd_utmp != -1 )                    /* don't close if not   */
                close( fd_utmp );               /* open                 */
}

utmplib.h：

#ifndef UTMPLIB_H
#define UTMPLIB_H

/* This file was automatically generated.  Do not edit! */
utmp_close();
int utmp_reload();
struct utmp *utmp_next();
utmp_open(char *filename);

#endif

但是我无法编译这些文件，我收到了这个错误：

who.h:9:6: error: conflicting types for ‘show_info’
 void show_info(struct utmp *utbufp);

我没有写这两个文件。首先，为什么有重复的声明？我该如何解决？

我使用makeheaders生成了头文件。

实际上这些文件是Linux中的who命令或GNU核心工具中的who.c的基本版本的示例。 Taken from here

who.c编译没有任何错误并无缝工作（如果你用main更改Who函数名称）：

cc who.c utmplib.c -o who
who

Answer 1

使用automake时可以覆盖标志，例如'make CFLAGS = -O0 file.o'来禁用file.c的优化

重复的声明。错误：'functionname'的冲突类型

1 个答案: