Fopen, fread, And 1A

// ================================================ ========================================================== ======================================
// Title:
// Fopen, fread, And 1A
// Author:
// Norains
// Date:
// Friday 25-July-2006
// ================================================ ========================================================== ======================================
If fopen is not opened in binary mode, such as fopen (filename, "R"), the fread function stops reading as long as the file contains a byte of 1A. if fopen (filename, "rb") is used, this problem will not occur.
You can use the following code to read any PNG Image for verification. If fopen adopts the "r" method, fread can only read 5 bytes, because the sixth bit of the PNG image is 1A!
The Code is as follows (replace fopen with _ wfopen in EVC ):
Int getreadnum (lpctstr pcszfilename)
{
# Define max_read_num 10

File * PFS;
PFS = _ wfopen (pcszfilename, text ("R"); // PFS = _ wfopen (pcszfilename, text ("rb "));
If (PFS = NULL)
{
Return 0;
}
Int itype = img_nosupport;
Pbyte pbuffer = NULL;
Pbuffer = (pbyte) malloc (sizeof (byte) * max_read_num );
Int ireadnum = fread (pbuffer, sizeof (byte), max_read_num, PFS );
Free (pbuffer );
Return ireadnum;
}
Use this code to read PNG images. The returned value is 5! If fopen is "rb", everything is normal, it is 10!