ftell()
The ftell function obtains the current value of the file position indicator for the stream pointed to by f.
Synopsis
long ftell( file f);
Parameter
Parameter | Description |
---|---|
f | File with the wanted position. You can specify an absolute path or a relative path from the PROJ_PATH directory. |
Return value
In the event of errors, the function returns -1 or EOF otherwise, a position in bytes.
Error
If incorrect data types are used or if a file is not open.
Description
The ftell() function obtains the current value of the file position indicator for the stream pointed to by f.
Example
The following example opens a file, obtains the position of the pointer and sets the position to different
values:
main()
{
long tell, seek, offset, whence;
file f;
string dat, mod;
f=fopen("C:/TEMP/Abb.txt", "r+"); // Open file
// tell at the begin to 0
tell=ftell(f);
DebugN(tell); // 0
// set pointer to 30
seek=fseek(f, 30, SEEK_SET);
tell=ftell(f);
DebugN(tell);// 30
// set pointer to 30 from the current position
seek=fseek(f, 30, SEEK_CUR);
tell=ftell(f);
DebugN(tell); // 60
// set pointer to the end + 60
seek=fseek(f, 60, SEEK_END);
tell=ftell(f);
DebugN(tell); // 8224
// set pointer to the end
seek=fseek(f, 0, SEEK_END);
tell=ftell(f);
DebugN(tell); //8164
// set pointer again to end + 60
seek=fseek(f, 60, SEEK_CUR);
tell=ftell(f);
DebugN(tell); // 8224
}
Assignment
File functions
Availability
CTRL