fputs(3p) — Linux manual page


FPUTS(3P)               POSIX Programmer's Manual              FPUTS(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       fputs — put a string on a stream

SYNOPSIS         top

       #include <stdio.h>

       int fputs(const char *restrict s, FILE *restrict stream);

DESCRIPTION         top

       The functionality described on this reference page is aligned
       with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This
       volume of POSIX.1‐2017 defers to the ISO C standard.

       The fputs() function shall write the null-terminated string
       pointed to by s to the stream pointed to by stream.  The
       terminating null byte shall not be written.

       The last data modification and last file status change timestamps
       of the file shall be marked for update between the successful
       execution of fputs() and the next successful completion of a call
       to fflush() or fclose() on the same stream or a call to exit() or

RETURN VALUE         top

       Upon successful completion, fputs() shall return a non-negative
       number. Otherwise, it shall return EOF, set an error indicator
       for the stream, and set errno to indicate the error.

ERRORS         top

       Refer to fputc(3p).

       The following sections are informative.

EXAMPLES         top

   Printing to Standard Output
       The following example gets the current time, converts it to a
       string using localtime() and asctime(), and prints it to standard
       output using fputs().  It then prints the number of minutes to an
       event for which it is waiting.

           #include <time.h>
           #include <stdio.h>
           time_t now;
           int minutes_to_event;
           printf("The time is ");
           fputs(asctime(localtime(&now)), stdout);
           printf("There are still %d minutes to the event.\n",


       The puts() function appends a <newline> while fputs() does not.

       This volume of POSIX.1‐2017 requires that successful completion
       simply return a non-negative integer. There are at least three
       known different implementation conventions for this requirement:

        *  Return a constant value.

        *  Return the last character written.

        *  Return the number of bytes written. Note that this
           implementation convention cannot be adhered to for strings
           longer than {INT_MAX} bytes as the value would not be
           representable in the return type of the function. For
           backwards-compatibility, implementations can return the
           number of bytes for strings of up to {INT_MAX} bytes, and
           return {INT_MAX} for all longer strings.

RATIONALE         top

       The fputs() function is one whose source code was specified in
       the referenced The C Programming Language. In the original
       edition, the function had no defined return value, yet many
       practical implementations would, as a side-effect, return the
       value of the last character written as that was the value
       remaining in the accumulator used as a return value. In the
       second edition of the book, either the fixed value 0 or EOF would
       be returned depending upon the return value of ferror(); however,
       for compatibility with extant implementations, several
       implementations would, upon success, return a positive value
       representing the last byte written.



SEE ALSO         top

       Section 2.5, Standard I/O Streams, fopen(3p), putc(3p), puts(3p)

       The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017                         FPUTS(3P)

Pages that refer to this page: stdio.h(0p)puts(3p)