.\" Generated from openpam_straddch.c by gendoc.pl
.Dd June 27, 2023
.Dt OPENPAM_STRADDCH 3
.Os
.Sh NAME
.Nm openpam_straddch
.Nd add a character to a string, expanding the buffer if needed
.Sh SYNOPSIS
.In sys/types.h
.In security/pam_appl.h
.In security/openpam.h
.Ft "int"
.Fn openpam_straddch "char **str" "size_t *size" "size_t *len" "int ch"
.Sh DESCRIPTION
The
.Fn openpam_straddch
function appends a character to a dynamically
allocated NUL-terminated buffer, reallocating the buffer as needed.
.Pp
The
.Fa str
argument points to a variable containing either a pointer to
an existing buffer or
.Dv NULL .
If the value of the variable pointed to by
.Fa str
is
.Dv NULL ,
a new buffer
is allocated.
.Pp
The
.Fa size
and
.Fa len
argument point to variables used to hold the size
of the buffer and the length of the string it contains, respectively.
.Pp
The final argument,
.Fa ch ,
is the character that should be appended to
the string.  If
.Fa ch
is 0, nothing is appended, but a new buffer is
still allocated if
.Fa str
is NULL.  This can be used to
.Do
bootstrap
.Dc
the
string.
.Pp
If a new buffer is allocated or an existing buffer is reallocated to
make room for the additional character,
.Fa str
and
.Fa size
are updated
accordingly.
.Pp
The
.Fn openpam_straddch
function ensures that the buffer is always
NUL-terminated.
.Pp
If the
.Fn openpam_straddch
function is successful, it increments the
integer variable pointed to by
.Fa len
(unless
.Fa ch
was 0) and returns 0.
Otherwise, it leaves the variables pointed to by
.Fa str ,
.Fa size
and
.Fa len
unmodified, sets
.Va errno
to
.Dv ENOMEM
and returns -1.
.Pp
.Sh RETURN VALUES
The
.Fn openpam_straddch
function returns 0 on success and -1 on failure.
.Sh SEE ALSO
.Xr pam 3 ,
.Xr pam_strerror 3
.Sh STANDARDS
The
.Fn openpam_straddch
function is an OpenPAM extension.
.Sh AUTHORS
The
.Fn openpam_straddch
function and this manual page were
developed by
.An Dag-Erling Sm\(/orgrav Aq Mt des@des.no .