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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH getlogin 3C "18 May 2004" "SunOS 5.11" "Standard C Library Functions" .SH NAME getlogin, getlogin_r \- get login name .SH SYNOPSIS .LP .nf #include \fBchar *\fR\fBgetlogin\fR(\fBvoid\fR); .fi .LP .nf \fBchar *\fR\fBgetlogin_r\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 \fBgetlogin_r\fR(\fBchar *\fR\fIname\fR, \fBsize_t\fR \fInamesize\fR); .fi .SH DESCRIPTION .sp .LP The \fBgetlogin()\fR function returns a pointer to the login name as found in \fB/var/adm/utmpx\fR. It can be used in conjunction with \fBgetpwnam\fR(3C) to locate the correct password file entry when the same user \fBID\fR is shared by several login names. .sp .LP If \fBgetlogin()\fR is called within a process that is not attached to a terminal, it returns a null pointer. The correct procedure for determining the login name is to call \fBcuserid\fR(3C), or to call \fBgetlogin()\fR and if it fails to call \fBgetpwuid\fR(3C). .sp .LP The \fBgetlogin_r()\fR function has the same functionality as \fBgetlogin()\fR except that the caller must supply a buffer \fIname\fR with length \fInamelen\fR to store the result. The \fIname\fR buffer must be at least \fB_POSIX_LOGIN_NAME_MAX\fR bytes in size (defined in <\fBlimits.h\fR>). The POSIX version (see \fBstandards\fR(5)) of \fBgetlogin_r()\fR takes a \fInamesize\fR parameter of type \fBsize_t\fR. .SH RETURN VALUES .sp .LP Upon successful completion, \fBgetlogin()\fR returns a pointer to the login name or a null pointer if the user's login name cannot be found. Otherwise it returns a null pointer and sets \fBerrno\fR to indicate the error. .sp .LP The standard-conforming \fBgetlogin_r()\fR returns \fB0\fR if successful, or the error number upon failure. .SH ERRORS .sp .LP The \fBgetlogin_r()\fR function will fail if: .sp .ne 2 .mk .na \fB\fBERANGE\fR\fR .ad .RS 10n .rt The size of the buffer is smaller than the result to be returned. .RE .sp .ne 2 .mk .na \fB\fBEINVAL\fR\fR .ad .RS 10n .rt And entry for the current user was not found in the \fB/var/adm/utmpx\fR file. .RE .sp .LP The \fBgetlogin()\fR and \fBgetlogin_r()\fR functions may fail if: .sp .ne 2 .mk .na \fB\fBEMFILE\fR\fR .ad .RS 10n .rt There are {\fBOPEN_MAX\fR} file descriptors currently open in the calling process. .RE .sp .ne 2 .mk .na \fB\fBENFILE\fR\fR .ad .RS 10n .rt The maximum allowable number of files is currently open in the system. .RE .sp .ne 2 .mk .na \fB\fBENXIO\fR\fR .ad .RS 10n .rt The calling process has no controlling terminal. .RE .sp .LP The \fBgetlogin_r()\fR function may fail if: .sp .ne 2 .mk .na \fB\fBERANGE\fR\fR .ad .RS 10n .rt The size of the buffer is smaller than the result to be returned. .RE .SH USAGE .sp .LP The return value of \fBgetlogin()\fR points to thread-specific data whose content is overwritten on each call by the same thread. .sp .LP Three names associated with the current process can be determined: \fBgetpwuid(\fR\fBgeteuid()\fR\fB)\fR returns the name associated with the effective user ID of the process; \fBgetlogin()\fR returns the name associated with the current login activity; and \fBgetpwuid(\fR\fBgetuid()\fR\fB)\fR returns the name associated with the real user ID of the process. .SH FILES .sp .ne 2 .mk .na \fB\fB/var/adm/utmpx\fR\fR .ad .RS 18n .rt user access and administration information .RE .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ Interface StabilityStandard _ MT-LevelSee below. .TE .SH SEE ALSO .sp .LP \fBgeteuid\fR(2), \fBgetuid\fR(2), \fBcuserid\fR(3C), \fBgetgrnam\fR(3C), \fBgetpwnam\fR(3C), \fBgetpwuid\fR(3C), \fButmpx\fR(4), \fBattributes\fR(5), \fBstandards\fR(5) .SH NOTES .sp .LP When compiling multithreaded programs, see \fBIntro\fR(3). .sp .LP The \fBgetlogin()\fR function is safe to use in multithreaded applications, but is discouraged. The \fBgetlogin_r()\fR function should be used instead. .sp .LP Solaris 2.4 and earlier releases provided a \fBgetlogin_r()\fR 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 may not be supported in future releases. New applications and libraries should use the standard-conforming interface.