1fputc(3C) Standard C Library Functions fputc(3C)
2
6 fputc, putc, putc_unlocked, putchar, putchar_unlocked, putw - put a
7 byte on a stream
8
10 #include <stdio.h>
11 int fputc(int c, FILE *stream);
13 int putc(int c, FILE *stream);
16 int putc_unlocked(int c, FILE *stream);
19 int putchar(int c);
22 int putchar_unlocked(int c);
25 int putw(int w, FILE *stream);
28
31 The fputc() function writes the byte specified by c (converted to an
32 unsigned char) to the output stream pointed to by stream, at the posi‐
33 tion indicated by the associated file-position indicator for the stream
34 (if defined), and advances the indicator appropriately. If the file
35 cannot support positioning requests, or if the stream was opened with
36 append mode, the byte is appended to the output stream.
37 The st_ctime and st_mtime fields of the file will be marked for update
40 between the successful execution of fputc() and the next successful
41 completion of a call to fflush(3C) or fclose(3C) on the same stream or
42 a call to exit(3C) or abort(3C).
43 The putc() routine behaves like fputc(), except that it is implemented
46 as a macro. It runs faster than fputc(), but it takes up more space per
47 invocation and its name cannot be passed as an argument to a function
48 call.
49 The call putchar(c) is equivalent to putc(c, stdout). The putchar()
52 routine is implemented as a macro.
53 The putc_unlocked() and putchar_unlocked() routines are variants of
56 putc() and putchar(), respectively, that do not lock the stream. It is
57 the caller's responsibility to acquire the stream lock before calling
58 these routines and releasing the lock afterwards; see flockfile(3C) and
59 stdio(3C). These routines are implemented as macros.
60 The putw() function writes the word (that is, type int) w to the output
63 stream (at the position at which the file offset, if defined, is point‐
64 ing). The size of a word is the size of a type int and varies from
65 machine to machine. The putw() function neither assumes nor causes
66 special alignment in the file.
67 The st_ctime and st_mtime fields of the file will be marked for update
70 between the successful execution of putw() and the next successful com‐
71 pletion of a call to fflush(3C) or fclose(3C) on the same stream or a
72 call to exit(3C) or abort(3C).
73
75 Upon successful completion, fputc(), putc(), putc_unlocked(),
76 putchar(), and putchar_unlocked() return the value that was written.
77 Otherwise, these functions return EOF, the error indicator for the
78 stream is set, and errno is set to indicate the error.
79 Upon successful completion, putw() returns 0. Otherwise, it returns a
82 non-zero value, sets the error indicator for the associated stream, and
83 sets errno to indicate the error.
84 An unsuccessful completion will occur, for example, if the file associ‐
87 ated with stream is not open for writing or if the output file cannot
88 grow.
89
91 The fputc(), putc(), putc_unlocked(), putchar(), putchar_unlocked(),
92 and putw() functions will fail if either the stream is unbuffered or
93 the stream's buffer needs to be flushed, and:
94 EAGAIN The O_NONBLOCK flag is set for the file descriptor underlying
96 stream and the process would be delayed in the write opera‐
97 tion.
98 EBADF The file descriptor underlying stream is not a valid file
101 descriptor open for writing.
102 EFBIG An attempt was made to write to a file that exceeds the maxi‐
105 mum file size or the process' file size limit.
106 EFBIG The file is a regular file and an attempt was made to write
109 at or beyond the offset maximum.
110 EINTR The write operation was terminated due to the receipt of a
113 signal, and no data was transferred.
114 EIO A physical I/O error has occurred, or the process is a mem‐
117 ber of a background process group attempting to write to its
118 controlling terminal, TOSTOP is set, the process is neither
119 ignoring nor blocking SIGTTOU and the process group of the
120 process is orphaned. This error may also be returned under
121 implementation-dependent conditions.
122 ENOSPC There was no free space remaining on the device containing
125 the file.
126 EPIPE An attempt is made to write to a pipe or FIFO that is not
129 open for reading by any process. A SIGPIPE signal will also
130 be sent to the calling thread.
131 The fputc(), putc(), putc_unlocked(), putchar(), putchar_unlocked(),
135 and putw() functions may fail if:
136 ENOMEM Insufficient storage space is available.
138 ENXIO A request was made of a non-existent device, or the request
141 was outside the capabilities of the device.
142
145 Functions exist for the putc(), putc_unlocked(), putchar(), and
146 putchar_unlocked() macros. To get the function form, the macro name
147 must be undefined (for example, #undef putc).
148 When the macro forms are used, putc() and putc_unlocked() evaluate the
151 stream argument more than once. In particular, putc(c, *f++); does not
152 work sensibly. The fputc() function should be used instead when evalu‐
153 ating the stream argument has side effects.
154 Because of possible differences in word length and byte ordering, files
157 written using putw() are implementation-dependent, and possibly cannot
158 be read using getw(3C) by a different application or by the same appli‐
159 cation running in a different environment.
160 The putw() function is inherently byte stream oriented and is not ten‐
163 able in the context of either multibyte character streams or wide-char‐
164 acter streams. Application programmers are encouraged to use one of the
165 character-based output functions instead.
166
168 See attributes(5) for descriptions of the following attributes:
169 ┌─────────────────────────────┬─────────────────────────────┐
174 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
175 ├─────────────────────────────┼─────────────────────────────┤
176 │Interface Stability │fputc(), putc(), │
177 │ │putc_unlocked(), putchar(), │
178 │ │and putchar_unlocked() are │
179 │ │Standard. │
180 ├─────────────────────────────┼─────────────────────────────┤
181 │MT-Level │See NOTES below. │
182 └─────────────────────────────┴─────────────────────────────┘
183
185 getrlimit(2), ulimit(2) write(2), Intro(3), abort(3C), exit(3C),
186 fclose(3C), ferror(3C), fflush(3C), flockfile(3C), fopen(3UCB),
187 printf(3C), putc(3C), puts(3C), setbuf(3C), stdio(3C), attributes(5),
188 standards(5)
189
191 The fputc(), putc(), putchar(), and putw() routines are MT-Safe in mul‐
192 tithreaded applications. The putc_unlocked() and putchar_unlocked()
193 routines are unsafe in multithreaded applications.
194SunOS 5.11 1 Nov 2003 fputc(3C)