#ifndef __GAPREAD_H
#define __GAPREAD_H
#endif

#ifdef __cplusplus
extern "C" {
#endif

/*-----------------------------------------------------------------------------*/
int GAPopenfile( char* fname, char** probname );
/*------------------------------------------------------------------------------
PURPOSE:
Opens a file named fname as a "GAPFILE" for reading and returns the "problem name",
that is the filename without path and extension. 

PARAMETERS:
- fname   : pointer to an array of chars containing the name of the data file
- probname: if probname is not NULL on input, the problem's name is
            returned on output in *probname.

RETURN VALUE: 0 on success, 1 if file unable to open file, 2 if error
              occurred while reading number of instances	    
-------------------------------------------------------------------------------*/

/*-----------------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "gapread.h"





static FILE*    GAPfile=NULL;   /* Handle to the data file                     */
static int      GAPnuminst=0;   /* number of problem instances in input file   */
static int      GAPcurinst=0;   /* current problem instance                    */

static char*    GAPpname=NULL;  /* problem name                                */
static double** GAPprofit=NULL; /* GAPprofit[i][j] is the profit of assigning
                                   job j to agent i                            */
static int**    GAPweight=NULL; /* GAPweight[i][j] is resource requirement
                                   of assigning job j to agent i               */
static int*     GAPcap=NULL;    /* GAPcap[i] is agent i's capacity             */

static double*  GAPpptr=NULL;   /* pointer to profits of assigning jobs stored */
                                /* as one array                                */

static int*     GAPwptr=NULL;   /* pointer to weights of assigning jobs stored */
                                /* as one array                                */

/*-----------------------------------------------------------------------------*/

int GAPopenfile( char* fname, char** probname ) {

/*
  Description:
  ------------
  Opens file named fname as a "GAPFILE" for reading, records the number of
  problem instances contained in the data file and returns the "problem name",
  that is the filename without path and extension.

  Parameters:
  ------------
  - fname   : pointer to an array of chars containing the name of the data file
  - probname: pointer to pointer to an array of chars that on output contains
              the problem name

  Return value:
  ------------
  - 0 on success
  - 1 if file fname could not be found
  - 2 if error on reading number of instances has occurred

  Scope: Export
  -------------
*/
  char *cptr = strrchr ( fname, (int)'/' );
  char *aline=NULL, *token=NULL;
  const char delim[] = " ";
  int   num, len;

  /* Open the data file */
  GAPnuminst = 0;
  GAPcurinst = 0;
  GAPpname   = NULL;
  GAPprofit  = NULL;
  GAPweight  = NULL;
  GAPcap     = NULL;
  if ( probname ) *probname = NULL;
  GAPfile = fopen( fname, "r" );
  if ( GAPfile == NULL ) return( 1 );

  /* Get the problem name from the file name */
  if ( cptr == NULL ) cptr = fname; else cptr++;
  GAPpname = strdup( cptr );

  /* Check if file has info about number of problem instances in data file */
  aline = (char*) malloc( 1000 );
  num   = getline(&aline,&len,GAPfile);
  token = strtok( aline, delim );
  num   = 0;
  while ( token != NULL ) {
    num++;
    token = strtok ( NULL, delim );
  }
  fclose( GAPfile );
  free(aline);

  /* Reopen file and read number of instances */
  GAPfile    = fopen( fname, "r" );
  GAPnuminst = 1;
  if ( num == 1 ) {
    if ( fscanf(GAPfile,"%d\n",&GAPnuminst) != 1 ) return( 2 );
  }

  if ( probname ) *probname = GAPpname;
  return( 0 );

}

Compiling is ok
Linking...
1>gapread.obj : error LNK2019: unresolved external symbol _getline referenced in function _GAPopenfile
1>MSVCRTD.lib(crtexe.obj) : error LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup
1>C:\Documents and Settings\tuec\My Documents\Reader\Debug\Reader.exe : fatal error LNK1120: 2 unresolved externals

ssize_t getline (char **lineptr, size_t *n, FILE *stream);