Bug 138663 - system(3) man page confuses users about "return value of 127"
Summary: system(3) man page confuses users about "return value of 127"
Status: Open
Alias: None
Product: Documentation
Classification: Unclassified
Component: Manual Pages (show other bugs)
Version: Latest
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-bugs (Nobody)
Depends on:
Reported: 2009-09-09 15:20 UTC by Gennady Proskurin
Modified: 2018-04-10 22:58 UTC (History)
1 user (show)

See Also:

system.txt (488 bytes, text/plain; charset=UTF-8)
2014-05-30 20:42 UTC, Sevan Janiyan
no flags Details

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Description Gennady Proskurin freebsd_committer 2009-09-09 15:20:00 UTC
from system(3) man page

     The system() function returns the exit status of the shell as returned by
     waitpid(2), or -1 if an error occurred when invoking fork(2) or
     waitpid(2).  A return value of 127 means the execution of the shell

It should be clearly mentioned, that "return value of 127" applies to result of WEXITSTATUS() or something (termination status for a program), not to return value of system() itself.


man from OpenBSD, for example:

     If a child process cannot be created, or the termination status of the
     shell cannot be obtained, system() returns -1 and sets errno to indicate
     the error.  If execution of the shell fails, system() returns the termi-
     nation status for a program that terminates with a call of exit(127).
How-To-Repeat: man 3 system
read section "RETURN VALUES"
Comment 1 Glen Barber freebsd_committer 2010-09-14 03:16:13 UTC
Responsible Changed
From-To: freebsd-doc->gjb

I'll take this.
Comment 2 Glen Barber freebsd_committer 2010-10-01 12:50:49 UTC
Responsible Changed
From-To: gjb->freebsd-doc

Back to the pool for now due to lack of time.
Comment 3 Eitan Adler freebsd_committer freebsd_triage 2012-03-05 00:22:38 UTC
Responsible Changed
From-To: freebsd-doc->eadler

I'll take it.
Comment 4 Eitan Adler freebsd_committer freebsd_triage 2012-07-25 07:49:27 UTC
Responsible Changed
From-To: eadler->freebsd-doc

I won't be getting to this any time soon
Comment 5 Joel Dahl freebsd_committer 2013-04-22 12:05:48 UTC
Responsible Changed
From-To: freebsd-doc->Take
Comment 6 Joel Dahl freebsd_committer 2013-04-22 12:06:17 UTC
Responsible Changed
From-To: Take->joel

Comment 7 Eitan Adler freebsd_committer freebsd_triage 2017-12-31 07:58:34 UTC
For bugs matching the following criteria:

Status: In Progress Changed: (is less than) 2014-06-01

Reset to default assignee and clear in-progress tags.

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