fread

Header File

stdio.h

Category

Input/output Routines

Prototype

size_t fread(void *ptr, size_t size, size_t n, FILE *stream);

Description

Reads data from a stream.

fread reads n items of data each of length size bytes from the given input stream into a block pointed to by ptr.

The total number of bytes read is (n * size).

Return Value

On success fread returns the number of items (not bytes) actually read.

On end-of-file or error it returns a short count (possibly 0).

Example

Copy Code

#include <string.h>
#include <stdio.h>
int main(void)
{
   FILE *stream;
   char msg[] = "this is a test";
   char buf[20];
   if ((stream = fopen("DUMMY.FIL", "w+"))
       == NULL)
   {
      fprintf(stderr, "Cannot open output file.\n");
      return 1;
   }
   /* write some data to the file */
   fwrite(msg, strlen(msg)+1, 1, stream);
   /* seek to the beginning of the file */
   fseek(stream, SEEK_SET, 0);
   /* read the data and display it */
   fread(buf, strlen(msg)+1, 1, stream);
   printf("%s\n", buf);
   fclose(stream);
   return 0;
}

Portability

POSIX	Win32	ANSI C	ANSI C++
+	+	+	+

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