November 2000 Listing 1

#include <stdlib.h>
#include <stdio.h>
#include "toolhelp.h"
#include <commdlg.h>

typedef unsigned long ULONG;

BOOL OpenTheFile (void)
{
typedef enum {ekOK, ekFDia, ekOpen, ekFSiz, ekFZro, ekGAlo,
                ekRdFi, ekRdZr, ekProc} terrKind;
typedef char* terrMsgs[ekProc+1];
terrKind errKind = ekOK;
static terrMsgs errMsgs = { "No Error", "File Not Fnd",
                              "Cant Open","Invalid FSize",
                              "File Empty", "Alloc Error",
                              "File Read Err", "No Bytes Read",
                              "Process Err" };
HANDLE hFile = (HANDLE)-1;
ULONG ulCount, ulFilSiz;
OPENFILENAME Ofn;
char szFile[MAX_PATH+1] = "\0";
char *lpBuf = NULL;
BOOL bRet = FALSE;

if (!GetOpenFileName(&Ofn))                 errKind=ekFDia;
else if ((hFile=CreateFile(…))==(HANDLE)-1) errKind=ekOpen;
else if ((ulFilSiz=GetFileSize(...))==0xFF) errKind=ekFSiz;
else if (ulFilSiz == 0)                     errKind=ekFZro;
else if ((lpBuf=GlobalAlloc(...))==NULL)    errKind=ekGAlo;
else if (!ReadFile(hFile, ..., &ulCount))   errKind=ekRdFi;
else if (ulCount==0)                        errKind=ekRdZr;
else if (!ProcessTheFile(lpBuf))            errKind=ekProc;

if (lpBuf) GlobalFree(lpBuf);
if (hFile!=(HANDLE)-1) CloseHandle(hFile);
if (errKind!=ekOK) MessageBox(NULL, errMsgs[errKind]);
else bRet = TRUE;

return bRet;
}