Home / Get file size under windows

Windows doesn’t have an API to get a file size based on file name. This small function does that. It returns -1 if a file doesn’t exist. It doesn’t handle files > 2 GB (max positive number for 32 bit signed value). It’s quite easy to extend it to 64-bits if you know what is the 64 bit integer type in your compiler (unfortunately there’s no standard). A better design might be BOOL GetFileSize(const TCHAR *fileName, unsigned long *fileSizeOut) i.e. returning false if file doesn’t exist and putting the file size into fileSizeOut. “`c long GetFileSize(const TCHAR *fileName) {

BOOL                        fOk;
WIN32_FILE_ATTRIBUTE_DATA   fileInfo;

if (NULL == fileName)
    return -1;

fOk = GetFileAttributesEx(fileName, GetFileExInfoStandard, (void*)&fileInfo);
if (!fOk)
    return -1;
assert(0 == fileInfo.nFileSizeHigh);
return (long)fileInfo.nFileSizeLow;

} “`

Go to index of articles.