NAME

putc, putchar, fputc, putw − put character or word on a stream

SYNOPSIS

#include <stdio.h>

int putc (c, stream)
char c;
FILE ∗stream;

int putchar (c)
char c;

int fputc (c, stream)
char c;
FILE ∗stream;

int putw (w, stream)
int w;
FILE ∗stream;

DESCRIPTION

Putc writes the character c onto the output stream (at the position where the file pointer, if defined, is pointing).  Putchar(c) is defined as putc(c, stdout). Putc and putchar are macros. 

Fputc behaves like putc, but is a function rather than a macro. Fputc runs more slowly than putc, but takes less space per invocation.

Putw writes the word (32-bit integer on the 68000) w to the output stream (at the position at which the file pointer, if defined, is pointing).  Putw neither assumes nor causes special alignment in the file. 

Output streams, with the exception of the standard error stream stderr, are by default buffered if the output refers to a file and line-buffered if the output refers to a terminal. The standard error output stream stderr is by default unbuffered, but use of freopen (see fopen(3S)) will cause it to become buffered or line-buffered. When an output stream is unbuffered information is queued for writing on the destination file or terminal as soon as written; when it is buffered many characters are saved up and written as a block; when it is line-buffered each line of output is queued for writing on the destination terminal as soon as the line is completed (that is, as soon as a new-line character is written or terminal input is requested). setbuf(3S) may be used to change the stream’s buffering strategy.

SEE ALSO

fclose(3S), ferror(3S), fopen(3S), fread(3S), printf(3S), puts(3S), setbuf(3S). 

DIAGNOSTICS

On success, these functions each return the value they have written.  On failure, they return the constant EOF.  This will occur if the file stream is not open for writing, or if the output file cannot be grown.  Because EOF is a valid integer, ferror(3S) should be used to detect putw errors. 

BUGS

Because it is implemented as a macro, putc treats incorrectly a stream argument with side effects.  In particular, putc(c, ∗f++); doesn’t work sensibly.  Fputc should be used instead. 
Because of possible differences in word length and byte ordering, files written using putw are machine-dependent, and may not be read using getw on a different processor.  For this reason the use of putw should be avoided. 

Version 2.5  —  April 22, 1987