fwrite

Remonter à Stdio.h - Index

Header File

stdio.h

Category

Input/output Routines

Prototype

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

Description

Writes to a stream.

fwrite appends n items of data each of length size bytes to the given output file. The data written begins at ptr. The total number of bytes written is (n x size). ptr in the declarations is a pointer to any object.

Return Value

On successful completion fwrite returns the number of items (not bytes) actually written.

On error it returns a short count.

Example

 #include <stdio.h>
 struct mystruct
 {
   int i;
   char ch;
 };
 int main(void)
 {
    FILE *stream;
    struct mystruct s;
    if ((stream = fopen("TEST.$$$", "wb")) == NULL) /* open file TEST.$$$ */
    {
       fprintf(stderr, "Cannot open output file.\n");
       return 1;
    }
    s.i = 0;
    s.ch = 'A';
    fwrite(&s, sizeof(s), 1, stream); /* write struct s to file */
    fclose(stream); /* close file */
    return 0;
 }

Portability

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