C library functions -ftell()
C Standard Library - <stdio.h>
Description
C Library Functionslong int ftell(FILE *stream)Returns the current file position of the given stream.
Declaration
The following is the declaration of the ftell() function.
long int ftell(FILE *stream)
Parameter
- stream-- This is a pointer to a FILE object that identifies the stream.
Return Value
This function returns the current value of the position indicator. If an error occurs, it returns -1L and the global variable errno is set to a positive value.
Example
The following example demonstrates the usage of the ftell() function.
#include <stdio.h>
int main ()
{
FILE *fp;
int len;
fp = fopen("file.txt", "r");
if( fp == NULL )
{
perror ("打开文件错误");
return(-1);
}
fseek(fp, 0, SEEK_END);
len = ftell(fp);
fclose(fp);
printf("file.txt 的总大小 = %d 字节\n", len);
return(0);
}
Suppose we have a text filefile.txt, whose content is as follows:
This is example.com
Let us compile and run the above program. If the file content is as shown above, this will produce the following result; otherwise, it will give different results based on the file content.
file.txt 的总大小 = 19 字节other extensions