.TH "FBB::Exec" "3bobcat" "2005\-2020" "libbobcat\-dev_5\&.07\&.00" "Executing Child Processes"

.PP 
.SH "NAME"
FBB::Exec \- Runs external programs
.PP 
.SH "SYNOPSIS"
\fB#include <bobcat/exec>\fP
.br 
Linking option: \fI\-lbobcat\fP 
.PP 
.SH "DESCRIPTION"
The \fBFBB::Exec\fP class offers a basic interface for calling external
programs (so\-called \fIchild processes\fP)\&. The standard streams of the child
processes are not handled by ttExec) objects: the parent\(cq\&s standard streams
are used by the child process\&. The \fIPATH\fP environment variable is not used
when calling child processes: child process programs must be specified using
paths\&.
.PP 
\fIExec\fP objects may repeatedly be used to execute the same or different
child processes\&. Before starting the next child process, the current child
process must have finished\&.
.PP 
Arguments passed to child processes may be surrounded by double or single
quotes\&. Arguments surrounded by double quotes have their double quotes
removed, while interpreting any escape\-sequences that may have been used
within\&. Arguments surrounded by single quotes have their single quotes
removed, while accepting their content as\-is\&. In addition unquoted
escape\-sequences may be specified: those escape sequences are evaluated and
replaced by their intended characters (e\&.g\&., \fI\e100\fP is converted to \fI@\fP)\&.
.PP 
.SH "NAMESPACE"
\fBFBB\fP
.br 
All constructors, members, operators and manipulators, mentioned in this
man\-page, are defined in the namespace \fBFBB\fP\&.
.PP 
.SH "INHERITS FROM"
\fBFBB::Fork\fP
.PP 
.SH "CONSTRUCTOR"

.PP 
Only the default constructor is supported\&.
.PP 
.SH "MEMBERS"

.PP 
.IP o 
\fBbool execute(std::string const &cmd)\fP:
.br 
The argument specifies the command to execute: the command itself must
be specified as a path (the \fIPATH\fP environment variable isn\(cq\&t used)\&. The
member returns \fItrue\fP if the child process\(cq\&s exit value equals 0\&. Otherwise
\fIfalse\fP is returned\&. Once \fIexecute\fP has returned it can be called again,
either using the same or another command\&. The class \fIExec\fP does not offer
facilities to forcefully terminate child processes: parent processes are
suspended until the child processes have completed\&. Arguments passed to the
program to be executed as child process may optionall be specified using
single or double quotes, as described in this man\-page\(cq\&s DESCRIPTION section\&.
.IP 
.IP o 
\fBint ret() const\fP:
.br 
Once \fIexecute\fP has returned this member provides the actual exit
code of the child process\&. Its value equals \-1 before the first \fIexectue\fP
call\&.

.PP 
.SH "EXAMPLE"

.PP 
.nf 
#include <iostream>
#include <bobcat/execfork>

using namespace std;
using namespace FBB;

int main()
{
    ExecFork ef;

    if (ef\&.execute(\(dq\&/bin/cp driver\&.cc /tmp\(dq\&))
        cout << \(dq\&driver\&.cc now copied to /tmp\en\(dq\&;
    else
        cout << \(dq\&could not copy driver\&.cc to /tmp\en\(dq\&;

    cout << \(dq\&Again:\en\(dq\&;

    if (ef\&.execute(\(dq\&/bin/cp driver\&.cc /tmp\(dq\&))
        cout << \(dq\&driver\&.cc now copied to /tmp\en\(dq\&;
    else
        cout << \(dq\&could not copy driver\&.cc to /tmp\en\(dq\&;

}

.fi 

.PP 
.SH "FILES"
\fIbobcat/exec\fP \- provides the class interface
.PP 
.SH "SEE ALSO"
\fBbobcat\fP(7), \fBcerrextractor\fP(3bobcat), \fBcininserter\fP(3bobcat),
\fBcoutextractor\fP(3bobcat), \fBexecl\fP(3), \fBfork\fP(3bobcat),
\fBprocess\fP(3bobcat), \fBstdextractor\fP(3bobcat)\&.
.PP 
.SH "BUGS"
None reported\&.
.PP 
.SH "BOBCAT PROJECT FILES"

.PP 
.IP o 
\fIhttps://fbb\-git\&.gitlab\&.io/bobcat/\fP: gitlab project page;
.IP o 
\fIbobcat_5\&.07\&.00\-x\&.dsc\fP: detached signature;
.IP o 
\fIbobcat_5\&.07\&.00\-x\&.tar\&.gz\fP: source archive;
.IP o 
\fIbobcat_5\&.07\&.00\-x_i386\&.changes\fP: change log;
.IP o 
\fIlibbobcat1_5\&.07\&.00\-x_*\&.deb\fP: debian package containing the
libraries;
.IP o 
\fIlibbobcat1\-dev_5\&.07\&.00\-x_*\&.deb\fP: debian package containing the
libraries, headers and manual pages;

.PP 
.SH "BOBCAT"
Bobcat is an acronym of `Brokken\(cq\&s Own Base Classes And Templates\(cq\&\&.
.PP 
.SH "COPYRIGHT"
This is free software, distributed under the terms of the 
GNU General Public License (GPL)\&.
.PP 
.SH "AUTHOR"
Frank B\&. Brokken (\fBf\&.b\&.brokken@rug\&.nl\fP)\&.
.PP