'\" -*- coding: UTF-8 -*-
.if \n(.g .ds T< \\FC
.if \n(.g .ds T> \\F[\n[.fam]]
.de URL
\\$2 \(la\\$1\(ra\\$3
..
.if \n(.g .mso www.tmac
.TH sg_init 3 2019-10-03 libstatgrab ""
.SH NAME
sg_init, sg_snapshot, sg_shutdown, sg_drop_privileges \- initialise libstatgrab
.SH SYNOPSIS
'nh
.nf
\*(T<#include <statgrab.h>\*(T>
.fi
.sp 1
.PP
.fi
.ad l
\*(T<void \fBsg_log_init\fR\*(T> \kx
.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
'in \n(.iu+\nxu
\*(T<(const char *\fIproperties_pfx\fR, const char *\fIenv_name\fR, const char *\fIargv0\fR);\*(T>
'in \n(.iu-\nxu
.ad b
.PP
.fi
.ad l
\*(T<sg_error \fBsg_init\fR\*(T> \kx
.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
'in \n(.iu+\nxu
\*(T<(int \fIignore_init_errors\fR);\*(T>
'in \n(.iu-\nxu
.ad b
.PP
.fi
.ad l
\*(T<sg_error \fBsg_snapshot\fR\*(T> \kx
.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
'in \n(.iu+\nxu
\*(T<(void);\*(T>
'in \n(.iu-\nxu
.ad b
.PP
.fi
.ad l
\*(T<sg_error \fBsg_shutdown\fR\*(T> \kx
.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
'in \n(.iu+\nxu
\*(T<(void);\*(T>
'in \n(.iu-\nxu
.ad b
.PP
.fi
.ad l
\*(T<sg_error \fBsg_drop_privileges\fR\*(T> \kx
.if (\nx>(\n(.l/2)) .nr x (\n(.l/5)
'in \n(.iu+\nxu
\*(T<(void);\*(T>
'in \n(.iu-\nxu
.ad b
'hy
.SH DESCRIPTION
\*(T<\fBsg_init\fR\*(T>() either initialises the statgrab
library and sets the initialisation counter to 1, if not already done,
or increases the initialisation counter.
If called for the first time (in fact: if called when the initialisation
counter is 0), the constructor (initialisation routine) of each
registered component is invoked, some global variables are
initialised, requested mutual exclusion semaphores are initialised
and so on.
\*(T<\fBsg_init\fR\*(T>() is protected by the mutex named
"statgrab".
.PP
\*(T<\fBsg_log_init\fR\*(T>() allows some application-individual
logging configuration. It's intended for projects with several applications
or commands which might have different appenders.
Mind that \*(T<\fBsg_log_init\fR\*(T> must be called before
\*(T<\fBsg_init\fR\*(T>, but after your application initialized
logging framework.
.PP
\*(T<\fBsg_snapshot\fR\*(T>() is Win32 only and will probably disappear.
.PP
\*(T<\fBsg_shutdown\fR\*(T>() decrements the initialisation
counter. If the counter reaches zero, components' destructors are
called, mutual exclusion semaphores (except "statgrab") are
destroyed etc.
\*(T<\fBsg_shutdown\fR\*(T>() is protected by the mutex named
"statgrab".
.PP
\*(T<\fBsg_drop_privileges\fR\*(T>() drops elevated privileges.
.SH "RETURN VALUES"
All functions return a statgrab error code. Either
SG_ERROR_NONE when everything was ok or the
appropriate error code from an constructor/destructor.
.SH EXAMPLE
Typical initialization/deinitialization sequence when using with log4cplus:

.nf
\*(T<
static void *l4cplus_initializer;

static void
cleanup_logging(void)
{
       log4cplus_deinitialize(l4cplus_initializer);
}

int
main(int argc, char const *argv[])
{
    l4cplus_initializer = log4cplus_initialize();
    atexit((void (*)(void))cleanup_logging);

    sg_log_init("saidar", "SAIDAR_LOG_PROPERTIES", argv[0]);
    sg_init(1);
    if(sg_drop_privileges() != 0) {
	die("Failed to drop setuid/setgid privileges");
    }

    do_something();

    sg_shutdown();

    return 0;
}
      \*(T>
.fi
.SH "SEE ALSO"
\fBstatgrab\fR(3)
.SH WEBSITE
\(lahttps://libstatgrab.org/\(ra