{{fbdoc item="title" value="EXEC"}}----
Temporarily transfers execution to an external program

{{fbdoc item="syntax"}}##
	[[KeyPgDeclare declare]] [[KeyPgSub function]] **Exec** ( [[KeyPgByref byref]] //program// [[KeyPgAs as]] [[KeyPgConstQualifier const]] [[KeyPgString string]], [[KeyPgByref byref]] //arguments// [[KeyPgAs as]] [[KeyPgConstQualifier const]] [[KeyPgString string]] ) [[KeyPgAs as]] [[KeyPgLong long]]
##
{{fbdoc item="usage"}}##
	//result// = **Exec**( //program//, //arguments// )
##
{{fbdoc item="param"}}
	##//program//##
		The file name (including file path) of the program (executable) to transfer control to.
	##//arguments//##
		The command-line arguments to be passed to the program.

{{fbdoc item="ret"}}
	The exit status of the program, or negative one (""-1"") if the program could not be executed.

{{fbdoc item="desc"}}
	Transfers control over to an external program. When the program exits, execution resumes immediately after the call to ##**Exec**##.

{{fbdoc item="ex"}}
{{fbdoc item="filename" value="examples/manual/system/exec.bas"}}%%(freebasic)
'A Windows based example but the same idea applies to Linux
CONST exename = "NoSuchProgram.exe"
CONST cmdline = "arg1 arg2 arg3"
DIM result AS INTEGER
result = EXEC( exename, cmdline )
IF result = -1 THEN
	PRINT "Error running "; exename
ELSE
	PRINT "Exit code:"; result
END IF
%%
{{fbdoc item="target"}}
	- Linux requires the //program// case matches the real name of the file. Windows and DOS  are case insensitive. The program being executed may be case sensitive for its command line parameters.
	- Path separators in Linux are forward slashes / . Windows uses backward slashes \ but it allows for forward slashes .  DOS uses backward  \ slashes. 
	- Exit code is limited to 8 bits in DOS.

{{fbdoc item="lang"}}
	- Not available in the //[[CompilerOptlang -lang qb]]// dialect unless referenced with the alias ##**""__Exec""**##.

{{fbdoc item="diff"}}
	- New to ""FreeBASIC""

{{fbdoc item="see"}}
	- ##[[KeyPgChain Chain]]## transfer temporarily, without arguments
	- ##[[KeyPgRun Run]]## one-way transfer
	- ##[[KeyPgCommand Command]]## pick arguments

{{fbdoc item="back" value="CatPgOpsys|Operating System Functions"}}