1FPUTS(3P) POSIX Programmer's Manual FPUTS(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 fputs — put a string on a stream
14
16 #include <stdio.h>
17 int fputs(const char *restrict s, FILE *restrict stream);
19
21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
24 defers to the ISO C standard.
25 The fputs() function shall write the null-terminated string pointed to
27 by s to the stream pointed to by stream. The terminating null byte
28 shall not be written.
29 The last data modification and last file status change timestamps of
31 the file shall be marked for update between the successful execution of
32 fputs() and the next successful completion of a call to fflush() or
33 fclose() on the same stream or a call to exit() or abort().
34
36 Upon successful completion, fputs() shall return a non-negative number.
37 Otherwise, it shall return EOF, set an error indicator for the stream,
38 and set errno to indicate the error.
39
41 Refer to fputc().
42 The following sections are informative.
44
46 Printing to Standard Output
47 The following example gets the current time, converts it to a string
48 using localtime() and asctime(), and prints it to standard output using
49 fputs(). It then prints the number of minutes to an event for which it
50 is waiting.
51 #include <time.h>
53 #include <stdio.h>
54 ...
55 time_t now;
56 int minutes_to_event;
57 ...
58 time(&now);
59 printf("The time is ");
60 fputs(asctime(localtime(&now)), stdout);
61 printf("There are still %d minutes to the event.\n",
62 minutes_to_event);
63 ...
64
66 The puts() function appends a <newline> while fputs() does not.
67 This volume of POSIX.1‐2008 requires that successful completion simply
69 return a non-negative integer. There are at least three known different
70 implementation conventions for this requirement:
71 * Return a constant value.
73 * Return the last character written.
75 * Return the number of bytes written. Note that this implementation
77 convention cannot be adhered to for strings longer than {INT_MAX}
78 bytes as the value would not be representable in the return type of
79 the function. For backwards-compatibility, implementations can
80 return the number of bytes for strings of up to {INT_MAX} bytes,
81 and return {INT_MAX} for all longer strings.
82
84 The fputs() function is one whose source code was specified in the ref‐
85 erenced The C Programming Language. In the original edition, the func‐
86 tion had no defined return value, yet many practical implementations
87 would, as a side-effect, return the value of the last character written
88 as that was the value remaining in the accumulator used as a return
89 value. In the second edition of the book, either the fixed value 0 or
90 EOF would be returned depending upon the return value of ferror(); how‐
91 ever, for compatibility with extant implementations, several implemen‐
92 tations would, upon success, return a positive value representing the
93 last byte written.
94
96 None.
97
99 Section 2.5, Standard I/O Streams, fopen(), putc(), puts()
100 The Base Definitions volume of POSIX.1‐2008, <stdio.h>
102
104 Portions of this text are reprinted and reproduced in electronic form
105 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
106 -- Portable Operating System Interface (POSIX), The Open Group Base
107 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
108 cal and Electronics Engineers, Inc and The Open Group. (This is
109 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
110 event of any discrepancy between this version and the original IEEE and
111 The Open Group Standard, the original IEEE and The Open Group Standard
112 is the referee document. The original Standard can be obtained online
113 at http://www.unix.org/online.html .
114 Any typographical or formatting errors that appear in this page are
116 most likely to have been introduced during the conversion of the source
117 files to man page format. To report such errors, see https://www.ker‐
118 nel.org/doc/man-pages/reporting_bugs.html .
119IEEE/The Open Group 2013 FPUTS(3P)