openpam_straddch(3)	add a character to a string, expanding the buffer if needed
openpam, openpam_borrow_cred, openpam_free_data, openpam_free_envlist, openpam_get_feature, openpam_get_option, openpam_log, openpam_nullconv, openpam_readline, openpam_readlinev, openpam_readword, openpam_restore_cred, openpam_set_feature, openpam_set_option, openpam_straddch, openpam_subst, openpam_ttyconv, pam_error, pam_get_authtok, pam_info, pam_prompt, pam_setenv, pam_verror, pam_vinfo, pam_vprompt(3)	Pluggable Authentication Modules Library

NAME

openpam_straddch — add a character to a string, expanding the buffer if needed

SYNOPSIS

#include <sys/types.h>
#include <security/pam_appl.h>
#include <security/openpam.h>

int
openpam_straddch(char **str, size_t *size, size_t *len, int ch);

DESCRIPTION

The openpam_straddch() function appends a character to a dynamically allocated NUL-terminated buffer, reallocating the buffer as needed.

The str argument points to a variable containing either a pointer to an existing buffer or NULL. If the value of the variable pointed to by str is NULL, a new buffer is allocated.

The size and len argument point to variables used to hold the size of the buffer and the length of the string it contains, respectively.

The final argument, ch, is the character that should be appended to the string. If ch is 0, nothing is appended, but a new buffer is still allocated if str is NULL. This can be used to “bootstrap” the string.

If a new buffer is allocated or an existing buffer is reallocated to make room for the additional character, str and size are updated accordingly.

The openpam_straddch() function ensures that the buffer is always NUL-terminated.

If the openpam_straddch() function is successful, it increments the integer variable pointed to by len (unless ch was 0) and returns 0. Otherwise, it leaves the variables pointed to by str, size and len unmodified, sets errno to ENOMEM and returns -1.

RETURN VALUES

The openpam_straddch() function returns 0 on success and -1 on failure.

STANDARDS

The openpam_straddch() function is an OpenPAM extension.

AUTHORS

The openpam_straddch() function and this manual page were developed by Dag-Erling Smørgrav <des@des.no>.