Chain

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Chain

Runs a program without arguments, waits, and returns its exit code or -1.

Syntax

Declare Function Chain ( ByRef program As Const String ) As Long

Parameters

• program

Description

Transfers control over to an external program. When the program exits, execution resumes immediately after the call to Chain.

Return Value

Returns the external program's exit code if executed successfully, or negative one (-1) otherwise.

Remarks

Usage

result = Chain( program )

Platform Differences

• Linux requires the program name case matches the real name of the file. Windows, DOS and a default macOS volume are case insensitive. The program chained may be case sensitive for its command line parameters. Path separators in Linux and macOS 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.

Differences from QB

• Common does not allow to keep the values of certain variables when chaining programs with Chain.

See also

• Exec transfer temporarily, with arguments
• Run one-way transfer
• Command pick arguments

Examples

#ifdef __FB_LINUX__

    Dim As String program = "./program"

#else

    Dim As String program = "program.exe"

#endif

Print "Running " & program & "..."

If (Chain(program) <> 0) Then

    Print program & " not found!"

End If

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Category: Operating System Functions
Kind: function

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Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.