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.TH TTYNAME 3C "Mar 31, 2005"
.SH NAME
ttyname, ttyname_r \- find pathname of a terminal
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>

\fBchar *\fR\fBttyname\fR(\fBint\fR \fIfildes\fR);
.fi

.LP
.nf
\fBchar *\fR\fBttyname_r\fR(\fBint\fR \fIfildes\fR, \fBchar *\fR\fIname\fR, \fBint\fR \fInamelen\fR);
.fi

.SS "Standard conforming"
.LP
.nf
cc [ \fIflag\fR...] \fIfile\fR ... \fB-D_POSIX_PTHREAD_SEMANTICS\fR [ \fIlibrary\fR ... ]

\fBint\fR \fBttyname_r\fR(\fBint\fR \fIfildes\fR, \fBchar *\fR\fIname\fR, \fBsize_t\fR \fInamesize\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBttyname()\fR function returns a pointer to a string containing the
null-terminated path name of the terminal device associated with file
descriptor \fIfildes\fR. The return value points to thread-specific data whose
content is overwritten by each call from the same thread.
.sp
.LP
The \fBttyname_r()\fR function has the same functionality as \fBttyname()\fR
except that the caller must supply a buffer \fIname\fR with length
\fInamelen\fR to store the result; this buffer must be at least
\fB_POSIX_PATH_MAX\fR in size (defined in <\fBlimits.h\fR>). The
standard-conforming version (see \fBstandards\fR(7)) of \fBttyname_r()\fR takes
a \fInamesize\fR parameter of type \fBsize_t\fR.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBttyname()\fR and \fBttyname_r()\fR return a
pointer to a string. Otherwise, a null pointer is returned and \fBerrno\fR is
set to indicate the error.
.sp
.LP
The standard-conforming \fBttyname_r()\fR returns 0 if successful or the error
number upon failure.
.SH ERRORS
.sp
.LP
The \fBttyname()\fR and \fBttyname_r()\fR functions may fail if:
.sp
.ne 2
.na
\fB\fBEBADF\fR\fR
.ad
.RS 10n
The \fIfildes\fR argument is not a valid file descriptor. This condition is
reported.
.RE

.sp
.ne 2
.na
\fB\fBENOTTY\fR\fR
.ad
.RS 10n
The \fIfildes\fR argument does not refer to a terminal device. This condition
is reported.
.RE

.sp
.LP
The \fBttyname_r()\fR function may fail if:
.sp
.ne 2
.na
\fB\fBERANGE\fR\fR
.ad
.RS 10n
The value of \fInamesize\fR is smaller than the length of the string to be
returned including the terminating null character.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	Safe
.TE

.SH SEE ALSO
.sp
.LP
.BR Intro (3),
.BR gettext (3C),
.BR setlocale (3C),
.BR attributes (7),
.BR standards (7)
.SH NOTES
.sp
.LP
When compiling multithreaded applications, see \fBIntro\fR(3), \fINotes On
Multithreaded Applications\fR.
.sp
.LP
Messages printed from this function are in the native language specified by the
\fBLC_MESSAGES\fR locale category. See \fBsetlocale\fR(3C).
.sp
.LP
The return value of \fBttyname()\fR points to thread-specific data whose
content is overwritten by each call from the same thread. This function is safe
to use in multithreaded applications, but its use is discouraged. The
\fBttyname_r()\fR function should used instead.
.sp
.LP
Solaris 2.4 and earlier releases provided definitions of the \fBttyname_r()\fR
interface as specified in POSIX.1c Draft 6. The final POSIX.1c standard changed
the interface as described above. Support for the Draft 6 interface is provided
for compatibility only and might not be supported in future releases. New
applications and libraries should use the standard-conforming interface.