freebsd-dev/lib/libc/stdio/fputs.3
Kyle Evans 12fe218f0b stdio: provide _unlocked variants of fflush, fputc, fputs, fread, fwrite
fflush_unlocked is currently desired in ports by sysutils/metalog, and
redefined as the locked fflush.

fputc_unlocked, fputs_unlocked, fread_unlocked, and fwrite_unlocked are
currently desired in ports by devel/elfutils, and redefined as the locked
fputs, fread, and fwrite respectively.

Reviewed by:	kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D23336
2020-01-30 03:31:16 +00:00

118 lines
3.2 KiB
Groff

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.\" @(#)fputs.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd January 23, 2020
.Dt FPUTS 3
.Os
.Sh NAME
.Nm fputs ,
.Nm fputs_unlocked ,
.Nm puts
.Nd output a line to a stream
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdio.h
.Ft int
.Fn fputs "const char *str" "FILE *stream"
.Ft int
.Fn fputs_unlocked "const char *str" "FILE *stream"
.Ft int
.Fn puts "const char *str"
.Sh DESCRIPTION
The function
.Fn fputs
writes the string pointed to by
.Fa str
to the stream pointed to by
.Fa stream .
.\" The terminating
.\" .Dv NUL
.\" character is not written.
.Pp
The
.Fn fputs_unlocked
function is equivalent to
.Fn fputs ,
except that the caller is responsible for locking the stream with
.Xr flockfile 3
before calling it.
This function may be used to avoid the overhead of locking the stream and to
prevent races when multiple threads are operating on the same stream.
.Pp
The function
.Fn puts
writes the string
.Fa str ,
and a terminating newline character,
to the stream
.Dv stdout .
.Sh RETURN VALUES
The functions
.Fn fputs
and
.Fn puts
return a nonnegative integer on success and
.Dv EOF
on error.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa stream
argument
is not a writable stream.
.El
.Pp
The functions
.Fn fputs
and
.Fn puts
may also fail and set
.Va errno
for any of the errors specified for the routines
.Xr write 2 .
.Sh SEE ALSO
.Xr ferror 3 ,
.Xr fputws 3 ,
.Xr putc 3 ,
.Xr stdio 3
.Sh STANDARDS
The functions
.Fn fputs
and
.Fn puts
conform to
.St -isoC .